Adhesive tape and method of making

ABSTRACT

An adhesive tape is provided which comprises a woven cloth, a polymer embedded into the cloth so as to cause the warp and weft fibers of the cloth to bond together at their overlapping points but not to completely encase the fibers, and a pressure sensitive adhesive coated onto at least a portion of the polymer, wherein the adhesive tape is hand tearable in the down-web and in the cross-web direction. A method of manufacturing such a tape is also provided.

This application is a division of application Ser. No. 08/577,855 filedDec. 22, 1995 which is now U.S. Pat. No. 5,795,834.

Related patent applications entitled Pressure-Sensitive Adhesive, Ser.No. 08/578,010; and Pressure-Sensitive Adhesive, Ser. No. 08/577,603;and Pressure-Sensitive Adhesive Suitable for Skin and Method ofPreparing, Ser. No. 08/577,923 52281USA8A; all assigned to 3M Companyand filed on the same day as this application are incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates to adhesive tapes with woven backings. Moreparticularly the invention relates to woven adhesive tapes that arewell-suited for medical uses and are hand tearable in the cross-web andin the web direction.

BACKGROUND

Cloth or cloth-like tapes are useful in numerous applications. Forexample, cloth-like tapes are used in medical applications where theytypically are adhered to skin. Most of the uses of cloth adhesive tapesin the medical market are for securing medical devices and lightimmobilization support. Some typical applications include securingendotracheal tubes, nasogastric tubes, and chest tubes, stabilizing bodysplints, and anchoring bulky wound dressings. Because these applicationsusually include contacting skin, one important desire for the tape isthat the adhesive adhere in moist or oily environments. Othercharacteristics often desired in cloth-like adhesive tapes ("woventapes") include a high tensile strength in the down and cross-webdirections and ease of tearing by hand in both the down and cross-webdirections along a substantially straight line without fraying. Cloth orcloth-like tapes are also used in industrial and commercial applicationssuch as in duct tapes, strapping tapes, electrical tapes, generalutility tapes and in abrasives to name a few.

Medical cloth tapes that are currently available are generallymanufactured using a densely woven cotton or synthetic cloth. As theweave density of the cloth used to manufacture adhesive tape increases,the strength of the resulting tape typically increases for the same sizefiber. Likewise, as the weave density of the cloth increases it iseasier to hand tear the resulting tape in a straight line. Medicalcloth-like tapes that are currently available typically comprise a wovencloth backing coated with a rubber based adhesive. Although the qualityof the cloth varies, a dense weave cotton is commonly used whichprovides adequate strength and allows tearing along a straight line.Natural rubber based adhesives are usually solvent coated and/orcalendered onto the backing and exhibit good adhesion to skin but cancause allergic reactions such as rashes. Several companies manufacturecloth-like adhesive tapes for medical uses. These tapes include Johnson& Johnson's Zonas Porous®, Kendall's Curity Porous®, and Beiersdorf'sLeukotape®. Each of these tapes consist of densely woven cotton clothscompletely coated or pattern coated with rubber based adhesives.

U.S. Pat. No. 2,352,463 to Wenzelberger et al. teaches interposing aflexible barrier sheet or baffle between the fabric and the adhesive toprevent the adhesive from substantially striking through the fabric ofthe tape. Wenzelberger et al. teach that this saves adhesive mass andavoids messy conditions as well as promoting the elasticity of thefabric without substantially increasing its weight. The Wenzelbergertape is prepared by knife spreading the elastic or pliable barrier sheetor film. The backing fabric of Wenzelberger may be a relatively closelywoven material, a coarse woven material or any conventional flexiblematerial.

U.S. Pat. No. 4,545,843 to Bray discloses an adhesive tape which ismanufactured by laminating at least one layer of heat activated adhesivefilm to one layer of a substrate material, and coating the therebyobtained laminate with a pressure sensitive adhesive. The film isspecifically a random copolymer of ethylene and acrylic acid. Theadhesive which is coated on the laminate cannot flow through thesubstrate, even if a porous substrate is used.

U.S. Pat. No. 3,853,598 to Raguse discloses an adhesive tape comprisedof a high thread count woven synthetic fabric, an acrylic latex primerwhich is either solvent-based or water-based, and an adhesive coated onthe primer side of the fabric. The primer bonds the warp and weftthreads together to produce a single sheet of material which may easilybe torn straight in either direction.

U.S. Pat. No. 3,616,146 to Gabet discloses preglued wall textiles whichare comprised of woven or nonwoven fabric which has been madehydrophobic, a continuous impermeable plastic resinous film adhered toone face of the fabric to minimize stretch and fraying, and a layer ofdry nontacky liquid-softenable adhesive coated on the exposed surface ofthe film.

U.S. Pat. No. 2,487,060 to Pike et al. discloses a barrier coat foradhesive sheets. The barrier coat is a synthetic rubber which provides auniform surface to prevent penetration of the adhesive into the porousbacking. The barrier coat is either coated from solvent or calenderedonto the porous backing.

U.S. Pat. No. 2,415,276 to Buckley et al. discloses a flexible wovenfabric backing with a layer of adhesive and an intermediate coatingcomposed of suitable rubber compositions which when vulcanized serve toprevent the adhesive from passing into the fabric's interstices. Theintermediate coating is either calendered onto the surface of the fabricor dispersed into a suitable solvent and then the solution is spreadevenly on the surface of the fabric backing. The Buckley et al.specification teaches at column 2 lines 24-29 that while theintermediate film adheres to the surface of the fabric it does not enterthe interstices of the fabric.

U.S. Pat. No. 2,187,563 to Thomas discloses an adhesive tape which isprepared by impregnating a woven fabric with wax-aluminumacetate-deacetylated chitin composition, drying, and thereafteranchoring on one side a rubber based pressure sensitive adhesive. U.S.Pat. No. 2,884,342 to Wolff teaches a pressure sensitive adhesive sheetmaterial which is comprised of a fabric backing impregnated with amixture of resinous materials and has a layer of adhesive materialapplied to one side. Impregnating results in woven fibers that areencased in a composition.

The art does not provide a tape which is both inexpensive to manufactureand exhibits the properties of a cloth-like adhesive tape. Theseproperties include a feel of cloth, the ability to be torn in a straightline without exerting undue force and without excessive frayingoccurring.

SUMMARY

The invention provides an adhesive tape which is inexpensive tomanufacture, is hand tearable in the cross-web and down-web directionsin a substantially straight line without fraying and exhibits tensilestrength suitable for medical, industrial and commercial applications.Further, the invention tape provides an adhesive tape that has the feelof cloth because the individual cloth fibers are not encased in eitheran adhesive or a polymer composition. The invention tape is comprised ofa cloth-like substrate, a polymer embedded into the cloth but notencasing the fibers of the cloth and a pressure sensitive adhesivecoated onto the polymer. A method of manufacturing the tape of theinvention is also included.

An adhesive tape is provided comprising a woven cloth, a polymerextrusion coated and embedded into the cloth and capable of adhering tothe cloth, and a pressure sensitive adhesive coated onto at least aportion of the polymer, wherein the adhesive tape is hand tearable in asubstantially straight line without fraying. The adhesive tape has acloth feel on the uncoated side. The polymer is selected from the groupof polyethylene elastomer, copolymers of polyethylene, blends ofpolyethylene and polyethylene copolymer, ethylene vinyl acetate,polyurethane, block copolymers, polyether block amides, acrylonitrilebutadiene styrene copolymer, polyester block copolymers, polypropylene,polycarbonate, polyacrylics, nylon and blends thereof.

An adhesive tape is provided which is comprised of a polyethylene-basedpolymer embedded into a woven cloth with an adhesive comprised of ablend of an acrylic and a thermoplastic elastomer coated on the polymerwherein the unwind tension of a roll of tape is less than 14 N/dmwithout using a low adhesion backsize. When torn by hand, the edges ofsuch an adhesive tape do not curl or fray.

An adhesive tape is provided which comprises a woven cloth, a polymerembedded into the cloth so as to cause the down-web and cross-web fibersof the cloth to bond together at their overlapping points but not tocompletely encase the fibers, and a pressure sensitive adhesive coatedonto at least a portion of the polymer, wherein the adhesive tape ishand tearable in a substantially straight line without fraying. Theadhesive composition is preferably comprised of a blend of an acrylicpressure-sensitive adhesive and a thermoplastic elastomer. The adhesivecomposition comprises at least 5 weight percent adhesive and thecomposition has a morphology comprising at least two distinct domains, afirst domain being substantially continuous in nature and a seconddomain being fibrillose to schistose in nature parallel to the majorsurface of the adhesive within said first domain. Optionally, theadhesive is comprised of a blend of an acrylic pressure-sensitiveadhesive and an elastomer and a tackifier, the composition comprising atleast 5 weight percent adhesive and the composition having a morphologycomprising at least two distinct domains, a first domain beingsubstantially continuous in nature and the second domain beingfibrillose to schistose in nature parallel to the major surface of theadhesive within the first domain.

A method of making an adhesive tape is also provided. The methodcomprises the steps of (a) providing a woven cloth substrate having afirst side and a second side, (b) applying a polymer onto the first sideof the substrate at a temperature, rate and amount to cause the fibersof the substrate to bind without causing the polymer to completelyencase the fibers of the cloth, and (c) coating a pressure sensitiveadhesive onto the polymer side of the polymer coated substrate whereinthe resulting adhesive tape is hand tearable in a substantially straightline without fraying.

An adhesive tape is provided which comprises a substrate comprised ofregularly spaced fibers in the down-web and cross-web directions whereinthe fibers are not woven, a polymer applied and partially embedded intothe substrate such that the down-web and cross-web fibers are notcompletely encased by the polymer, and a pressure sensitive adhesivecoated onto at least a portion of the polymer, wherein the adhesive tapeis hand tearable along a substantially straight line without fraying.

A composite backing is also provided, the backing comprising a substratehaving a first side and a second side, a polymer on the second side ofthe substrate and the polymer embedded into the substrate such that theoverlapping fibers of the substrate are bound together but the polymerdoes not extend through to the first side of the substrate, and whereinthe resulting composite backing is hand tearable along a substantiallystraight line without fraying.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a 50 times magnification light micrograph of a woven cloth foruse in the invention.

FIG. 2 is a 50 times magnification light micrograph of a comparativesample comprised of woven cloth solvent-coated with a polymer preparedby the method of Comparative Example 12.

FIG. 3 is a cross-sectional view of the sample of FIG. 2.

FIG. 4 is a 60 times magnification scanning electron micrograph (SEM) ofa top view of a sample of the invention.

FIG. 5 is a 60 times magnification SEM of a cross-sectional view of thesample of FIG. 4.

FIG. 6 is a 20 times magnification SEM of a top view of a comparativesample prepared by methods of Comparative Example 11.

FIG. 7 is a 100 times magnification SEM cross-sectional view of thecomparative sample of FIG. 6.

FIG. 8 is a light micrograph of a comparative sample of wovencloth/polymer backing which was torn in the cross-web direction; this isan unacceptable tear and is designated as a "1" tear described in thetest methods below.

FIG. 9 is a light micrograph of a comparative sample of wovencloth/polymer backing which was torn in the cross-web direction; this isan average tear and is designated as a "3" tear described in the testmethods below.

FIG. 10 is a light micrograph of a sample of woven cloth/polymer backingprepared according to the invention which was torn in the cross-webdirection; this is an excellent tear and is designated as a "5" teardescribed in the test methods below.

DEFINITIONS

"Cross-web" as used herein refers to the direction on a cloth or webwhich is perpendicular to the down-web direction.

"Delamination" as used herein refers to the polymer lifting and peelingaway from the cloth on a polymer/cloth composite backing.

"Down-web" as used herein refers to the direction that a cloth or web ismanufactured, the term is synonymous with "machine direction" or "webdirection."

"Extruding" as used herein refers to the process of placing a moltenmaterial on a web to obtain a composite material.

"Laminate" as used herein refers to the process and the productresulting from combining an existing film and a web in the presence ofheat.

"Low adhesion backsize" as used herein refers to any material applied toa tape backing to reduce the adhesion of the pressure sensitive adhesiveto the backing when unwinding a roll of tape.

"Pressure sensitive adhesive" as used herein refers to materials whichadhere to a substrate with no more than applied finger pressure and areaggressively and permanently tacky.

"Substrate" as used herein refers to a material having regularly spacedsubstantially parallel fibers in the down-web and cross-web directionand the fibers may or may not be interlaced in a weave.

"Woven" as used herein refers to strips, strands or fibers of materialthat are interlaced to form a cloth. The fibers are substantiallyparallel in the warp direction and substantially parallel in the weftdirection.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The cloth-like adhesive tape of the invention is comprised of at leastthree components. These include (1) a woven cloth or substrate, (2) apolymer, and (3) a pressure sensitive adhesive. Each of these componentsis described below along with a description of the necessary order ofthe components and the physical characteristics of the resultingadhesive tape.

Woven Cloth Substrate

A woven cloth of synthetic or natural fiber is useful in the presentinvention. If a substantially straight tear line is desired it isimportant that a nonwoven randomly oriented fiber web is not used. If awoven cloth is used, the perpendicular weave of the warp and weftthreads provide straight lines along which a propagated tear maycontinue. Alternatively a regularly spaced fibrous substrate may be usedin the invention. The substantially parallel down-web and cross-webthreads of the substrate provide straight lines along which theinvention tape can be torn. An example of such a substrate is CLAF®fabric as available from Amoco/Nisseki CLAF Inc. of Atlanta, Ga. It isdesirable that the tape of the invention is easily torn along a straightline since straight line tears result in less waste and result in tapesthat are easier to use than tapes that tear raggedly.

Any density weave of cloth is useful in the tape of the invention.Looser weave cloth generally permits lower costs and greaterconformability. Tighter weave cloth permits easier tear and highertensile properties for the same size fibers. Generally, as the weavedensity increases the cost of the cloth also increases. However, highdensity cloths are usually easier to tear than low density cloths. Asthe weave density of the cloth decreases, the cost of the cloth alsodecreases and the ability to tear the cloth in a straight linedecreases. As one will recognize, in order to reduce manufacturing costsit is desirable to use a low density weave cloth for cloth tapes sincethe raw material costs are reduced. The invention allows this withoutcompromising tearability of the tape.

Weave densities in the range of 5 warp threads per 2.5 cm (1 inch) by 5weft threads per 2.5 cm (1 inch) to 300 by 300 are useful in the presentinvention. Generally, a looser weave is used to prepare constructionsthat require increased conformability or decreased cost. Tighter weavesubstrates are used in constructions that require a high tensilestrength. In addition, unbalanced weave constructions are useful whenparticular performance properties are desired in one direction. Theperformance properties are not necessarily in the perpendiculardirection. For example, the greatest cross-web and down-web elongationoccurs when the fiber orientation is rotated 45 degrees. One skilled inthe art will recognize that it is necessary to assess the desiredperformance of the resulting tape when selecting the density of thewoven cloth. If drape is important a lower density weave is chosen,however, a lower density weave may require a thicker polymer layer ifexcellent tear properties are required. This is described more fullybelow. Therefore, the performance of the resulting tape is dependentupon several parameters, one of which includes the weave density of thewoven cloth.

The composition of the fibers of the woven cloth or of the substrate iseither natural or synthetic or a combination thereof. Examples ofnatural fibers include cotton, silk, hemp and flax Examples of syntheticfibers include rayon, polyester, acrylic, acrylate, polyolefin, nylonand glass. As with weave density, the choice of fibers which comprisethe woven cloth chosen to make the tape of the invention is dependentupon the cost, the desired feel or hand, drape, tensile strength,tearability and general performance of the resulting tape. Woven clothscomprised of synthetic fibers are generally less expensive than thosecomprised of natural fibers. However, the desired feel of a tapemanufactured from a natural fiber woven cloth may outweigh the costconsiderations when choosing the fiber content of the woven cloth. Onefeature of the invention is that the fibers of the substrate are notcompletely saturated with or encased in the polymer which is describedin more detail below. Thus, for example, if the tapes of the inventionare comprised of a woven cloth, the tapes maintain the feel of the wovencloth even though they also include a polymer in their construction. Oneskilled in the art will recognize the desired properties of a tape andwill choose the fiber content of the woven cloth or substrate tocorrelate with these properties.

Polymer

A polymer is applied to a woven cloth or substrate. The polymer is heatprocessable which allows one to apply the polymer onto the cloth orsubstrate via methods such as, for example, extrusion, lamination, orhot melt coating. Additionally, the polymer can be elastomeric whichallows any resulting tape to stretch across the bias of the woven cloth.Stretchability is desirable if the resultant tape is used for medicalpurposes since a tape which can stretch across the bias will improve apatient's comfort by allowing the tape to extend slightly as a result ofthe patient's movements. Polymers useful in the invention are thosewhich are melt processable and include thermoplastics, thermoplasticelastomers, and elastomers and blends thereof. Examples ofthermoplastics include but are not limited to polyolefins such asENGAGE™ 8200 available from Dow Chemical Co., ATTANE™ available from DowChemical Co., FLEXOMER™ 1137 and 1138 from Union Carbide, Linear-LowDensity Polyethylene 6806, available from Dow Chemical Co., Midland,Mich.; acrylonitrile-butadiene-styrene such as CYCOLAC™ DFA 1000R,available from General Electric, Pittfield, Mass.; nylon such as ZYTEL™159L, available from DuPont; polycarbonate such as LEXAN™ 101 availablefrom General Electric Plastics; polyvinyl chloride such as TEMPRITE™88203, available from BF Goodrich; and ethylene vinylacetate such asELVAX™ 240 and 40W; available from DuPont and ESCORENE™ LD312.09 fromExxon. Examples of thermoplastic elastomers include but are not limitedto linear, radial, star and tapered styrene-isoprene block copolymerssuch as KRATON™ D 1107P, available from Shell Chemical Co. andEUROPRENE™ SOL TE 9110, available from EniChem Elastomers Americas,Inc., linear styrene-(ethylene-butylene) block copolymers such asKRATON™ G1657, available from Shell Chemical Co., linearstyrene-ethylene-propylene) block copolymers such as KRATON™ G1750Xavailable from Shell Chemical Co., linear, radial, and starstyrene-butadiene block copolymers such as KRATON™ D1118X, availablefrom Shell Chemical Co. and EUROPRENE™ SOL TE 6205, available fromEniChem Elastomers Americas, Inc., and polyolefin elastomers based onmetallocene catalysis such as ENGAGE™ EG8200, available from DowPlastics Co. Examples of elastomers include but are not limited tonatural rubbers such as CV-60, a controlled viscosity grade, and SMR-5,a ribbed smoked sheet rubber, butyl rubbers, such as Exxon Butyl 268available from Exxon Chemical Co.; synthetic polyisoprenes such asCARIFLEX™, available from Royal Dutch Shell and NATSYN™ 2210, availablefrom Goodyear Tire and Rubber Co.; ethylene-propylenes; polybutadienes;polyisobutylenes such as VISTANEX™ MM L-80, available from ExxonChemical Co.; and styrene-butadiene random copolymer rubbers such asAMERIPOL™ 1011A, available from BF Goodrich

One feature of the invention is that the tape is hand tearable alongeach of the fiber directions. Without being bound by theory it isbelieved that the tape of the invention is hand tearable in bothdirections because the polymer effectively links and bonds the warp andweft fibers together at the overlap points. However, as explained aboveit is also a feature of the invention that the invention tape retainsthe feel of cloth which requires that the cloth fibers are not encased.When choosing the polymer it is important that the polymer will notcompletely penetrate the woven cloth so that the fibers comprising thecloth or substrate do not get encased or do not get completelysaturated.

Another feature of the invention is that the pressure sensitive adhesivecannot strike through the tape backing due to the construction of thebacking. The polymer successfully prohibits the adhesive frompenetrating the cloth or substrate. This feature is desirable for a fewreasons. First, the tape is less messy because the adhesive is onlypresent where the tape adheres to the substrate. Second, the tape iseasier to unwind from a roll because the adhesive does not penetrate thecloth. Third, if the tape is a medical tape it is more comfortable forthe patient if the adhesive does not penetrate the cloth and adhere tothe patient's bedding or to the patient's clothing. Alternatively, thepolymer can retard the migration of substances such as water into thepressure-sensitive adhesive.

The thickness of the polymer is dependent upon the desired properties ofthe tape and also on the weave density of the cloth or the fiber densityof the substrate. The ease with which the tape is torn and the drape ofthe tape are correlated to both the weave density and to the polymerthickness. As earlier stated, a tape manufactured with a low densityweave is traditionally more difficult to tear. However, as the lowdensity weave cloth is coated with thicker polymer layers which readilybond the crossover points of the warp and weft threads, the tape iseasier to tear. A thicker polymer layer may decrease the drape of thetape and create a stiff tape but may increase the ease with which it istorn. On the other hand, a high density weave cloth bonded with arelatively thin polymer layer may result in a tape which is easy to tearand exhibits good drape. That is, the tape is not stiff. One must assessthe desired properties and the cost of the tape to determine appropriatepolymer thickness. Preferably the polymer thickness of the inventiontape is in the range of about 12 and about 250 microns. Thinner polymerlayers generally exhibit better drape and conformability characteristicsthan thicker polymer layers but usually also require a higher densitycloth to retain tear properties. Tapes having constructions with thinpolymer layers and high density woven cloth are useful as medical tapes.Tape construction using thicker polymer layers generally allows looserweave substrates or lower modulus polymeric materials to exhibit goodtear properties. Such tape constructions are particularly suited forindustrial applications where stiffness is desired such as in duct tape.In choosing the polymer thickness one must also consider the processingparameters. This is described below.

With proper selection of polymeric material, indentations form on thepolymer side of the composite polymer/substrate construction which canresult in voids when a pressure-sensitive adhesive layer is applied.

The invention anticipates that the polymer layer is comprised of eithera single layer of polymer or is comprised of more than one layer ofpolymers having different properties. A multilayer polymer constructioncan be prepared as long as the properties described above areconsidered.

Fillers and dyes are optionally added to the polymer when otherproperties are also desired. Fillers may include colorants, plasticizersand antioxidants. For example, titanium oxide is added to the polymer ifa white tape is desired. Any filler or dye may be added to the tape aslong as it does not interfere with the polymer binding to the wovencloth.

Manufacturing the Polymer/Woven Cloth or Substrate Backing

The method of binding the woven cloth or substrate to the polymer toobtain the tape backing is important so that the tape of the inventionis obtained. A suitable method of coating the polymer on the woven clothor substrate is one which sufficiently embeds the polymer into the wovencloth causing the overlapping warp and weft threads to bond yet does notcause the polymer to completely penetrate and completely surround thefibers of the woven cloth. If the fibers of the woven cloth areimpregnated or encased or both by the polymer, the backing no longer hasmany of the desirable properties of cloth, that is, it no longer has thedrape or feel of cloth. Preparing the backing composite according to theinvention results in the desired properties of the invention. It resultsin a tape which is hand tearable in both the cross-web and down-webdirections without excessive fraying and also has the hand or feel ofcloth on its uncoated surface.

A suitable method of coating the polymer on the substrate is one whichsufficiently embeds the polymer into the substrate causing theoverlapping warp and weft threads to bond more tenaciously than they arealready bonded yet does not cause the polymer to completely penetrateand completely surround the fibers of the substrate. If the fibers ofthe substrate are impregnated or encased or both by the polymer, thebacking becomes considerably more stiff. Preparing the backing compositeaccording to the invention results in the desired properties of theinvention. It results in a tape which is hand tearable in both thecross-web and down-web directions without excessive fraying and does notimpregnate, saturate or completely encase the fibers.

Since the polymer does not encase the fibers of the woven cloth orsubstrate, the composite backing of the invention has two sides. Oneside is comprised of a substantially continuous polymer layer while thesecond side has the feel of cloth if a woven cloth is used. The Figuresillustrate the distinctions between the invention and composite backingsprepared by laminating a polymer to a cloth or saturating a cloth with apolymer. The methods of obtaining the samples shown in FIGS. 2, 3, 6 and7 are described in detail in Comparative Examples 11 and 12 below. FIGS.2 and 3 illustrate how the fibers of a woven cloth are completelysurrounded with polymer if a solution coating or impregnating method isused to coat the cloth. As stated earlier, this method of coatingresults in a composite backing which does not have the feel of cloth.This backing is also considerably more stiff than the composite backingsprepared by extruding the polymer onto the cloth. The samples in FIGS. 6and 7 were prepared by laminating a polymer film onto the cloth.Although this method of preparation does not entirely encase the clothfibers and provides a backing with the feel of cloth, it does notadequately bind the crossover points of the warp and weft threads. Tapesprepared by laminating a film to a cloth do not exhibit the samedesirable tear properties as the invention tapes. That is, the laminatedtapes do not readily tear along a straight line without fraying andwithout requiring the exertion of considerable force.

Compare the samples of FIGS. 2, 3, 6 and 7 with the samples of theinvention shown in FIGS. 4 and 5. The samples of FIGS. 4 and 5 wereprepared by extruding a polymer onto a woven cloth according to theprocedure described in Example 3 below. Polymer 18 is embedded into thefibers of the cloth 24 to provide adequate bonding of the crossoverpoints 20 and 22. However, the cloth fibers 24 are not encased with thepolymer providing a first cloth side and a second polymer side to thecomposite backing sample 26.

Preferably the polymer is extruded onto the woven cloth or substrate butother methods such as platen pressing a free film into the cloth orsubstrate are also acceptable. One drawback with the platen press methodis that it is not continuous and would be an expensive method ofmanufacturing the invention. Any other method of coating the polymeronto the cloth or substrate is acceptable if the polymer is sufficientlyembedded into the cloth or substrate so as to permanently weld thecrossover points of the warp and weft fibers together.

In order to embed the polymer into the cloth without allowing thepolymer to penetrate the cloth the processing parameters are carefullychosen. One skilled in the art recognizes that processing conditions aredependent upon the polymer used and the following temperature ranges areprovided merely as a general guideline. If a polyethylene-olefincopolymer is used the polymer is preferably extruded at a temperaturebetween 176° C. and 232° C., more preferably between 204° C. and 232°C., and most preferably between 204° C. and 218° C. The rate at whichthe polymer is extruded is another parameter which determines the depthto which the polymer is embedded into the woven cloth. If the polymer isnot embedded deep enough into the woven cloth to bind the overlappingfibers of the cloth, the cloth/polymer composite may be placed through acalender to apply enough force to bind the cross-over portions of thewarp and weft threads. If the post extrusion calendering is accomplishedit is necessary that not too much force is applied so that the polymerdoes not penetrate or completely encase the fibers of the woven cloth.

Adhesive

A pressure sensitive adhesive is coated onto the polymer side of thecomposite backing to obtain the tape of the invention. Any pressuresensitive adhesive is useful for preparing the tape of the invention.When choosing the appropriate pressure sensitive adhesive one mustconsider the intended use of the tape. For instance, if the tape is amedical tape the adhesive desirably has good initial adhesion, willtolerate the presence of moisture without releasing and the adhesionwill not build substantially over time. Other applications such asindustrial uses where a duct tape may adhere to steel or metal wouldrequire a different adhesive which is appropriate for the requiredperformance of the tape. This adhesive may require good initial adhesionwith a substantial increase in adhesion over time. Tolerance of thepresence of moisture probably is not as critical for industrial tapeadhesives as for adhesives used for medical applications.

Pressure sensitive adhesives require a delicate balance of viscous andelastic properties which result in a four-fold balance of adhesion,cohesion, stretchiness and elasticity. Pressure-sensitive adhesivesgenerally comprise elastomers which are either inherently tacky, orelastomers or thermoplastic elastomers which are extended with theaddition of tackifying resins and plasticizing oils. They can be coatedin solvent or as water-based emulsions to reduce the material viscosityto a level that is easily applied to the backing composite of theinvention.

Major classes of pressure-sensitive adhesives useful for preparing thetape of the invention include but are not limited to natural rubbers;synthetic rubbers such as butyl rubber, and linear, radial, star,branched and tapered block copolymers such as styrene-butadiene,styrene-ethylene/butylene and styrene-isoprene; acrylics, especiallythose having long chain alkyl groups; and silicones.

One pressure sensitive adhesive suitable for use in the invention iscomprised of a blend of about 5 to 95 weight percent of at least oneacrylic pressure-sensitive adhesive and about 5 to 95 weight percent ofat least one thermoplastic elastomeric material, the composition havinga morphology comprising at least two distinct domains, a first domainbeing substantially continuous in nature and a second domain beingfibrillose to schistose in nature parallel to the major surface of theadhesive composition within the first domain. The thermoplasticelastomeric material may optionally contain a tackifying resin orplasticizer, in which case it also may be an adhesive. This adhesive isprepared by (1) melt blending about 5 to 95 weight percent of at leastone acrylic pressure-sensitive adhesive and about 5 to 95 weight percentof at least one thermoplastic elastomeric material, (2) forming the meltblended materials under shear or extensional conditions or both orforming and drawing the melt blend, to form an adhesive composition andextruding the adhesive composition onto the polymer side of the backingcomposite of the invention to form a pressure-sensitive adhesive tape,the adhesive having a morphology comprising at least two distinctdomains, a first domain being substantially continuous in nature and thesecond domain being fibrillose to schistose in nature in the adhesiveforming direction with the first domain. Further aspects of preparingsuch an adhesive are detailed in copending U.S. patent application Ser.No. 08/578,010 entitled, "Pressure-Sensitive Adhesive," filed on evendate herewith, the text of which is incorporated by reference.

Alternatively the acrylic/thermoplastic elastomer blend is solventblended, knife coated and oven dried in order to drive the solvent fromthe adhesive. Such a solvent blended, solvent coated adhesive blend doesnot exhibit the morphology described in the previous paragraph for themelt blended, extruded adhesive blends. One skilled in the art maychoose the appropriate blending and coating techniques. An advantagewith using the melt-blending and extruding method is that it issolvent-free meaning that it is more environmentally friendly than thesolvent methods.

When preparing the acrylic/thermoplastic elastomer blend pressuresensitive adhesive, the following describes the acrylic pressuresensitive component used to prepare a suitable blend. Acrylicpressure-sensitive adhesives generally have a glass transitiontemperature of about -20° C. or less and may comprise from 100 to 80weight percent of a C₃ -C₁₂ alkyl ester component such as, for example,isooctyl acrylate, 2-ethyl-hexyl acrylate and n-butyl acrylate and from0 to 20 weight percent of a polar component such as, for example,acrylic acid, methacrylic acid, ethylene vinyl acetate, N-vinylpyrrolidone and styrene macromer. Preferably, the acrylicpressure-sensitive adhesives comprise from 0 to 20 weight percent ofacrylic acid and from 100 to 80 weight percent of isooctyl acrylate. Theacrylic pressure-sensitive adhesives may be self-tacky or tackified.Useful tackifiers for acrylics are rosin esters such as FORAL™ 85,available from Hercules, Inc., aromatic resins such as PICCOTEX™LC-55WK, available from Hercules, Inc., and aliphatic resins such asESCOREZ™ 1310LC, available from Exxon Chemical Co. Of course, such anacrylic adhesive is usefull in the present invention alone or formedinto a blended adhesive.

Thermoplastic elastomeric materials are materials which form at leasttwo phases at 21° C., have a glass transition temperature greater than50° C. and exhibit elastic properties in one of the phases.Thermoplastic elastomeric materials useful in the such a blend adhesiveinclude, for example, linear, radial, star and tapered styrene-isopreneblock copolymers such as KRATON™ D1107P, available from Shell ChemicalCo. and EUROPRENE™ SOL TE 9110, available from EniChem ElastomersAmericas, Inc., linear styrene-ethylene-butylene) block copolymers suchas KRATON™ G1657, available from Shell Chemical Co., linearstyrene-ethylene-propylene) block copolymers such as KRATON™ G1750X,available from Shell Chemical Co., linear, radial, and starstyrene-butadiene block copolymers such as KRATON™ D1118X, availablefrom Shell Chemical Co. and EUROPRENE™ SOL TE 6205, available fromEniChem Elastomers Americas, Inc., and polyolefin elastomers based onmetallocene catalysis such as ENGAGE™ EG8200, available from DowPlastics Co., and polyetherester elastomers such as HYTREL™ G3548,available from DuPont.

Another suitable adhesive for use in the present adhesive includes apressure sensitive adhesive blend comprised of an acrylic pressuresensitive adhesive and an elastomer with a tackifier. The adhesivecomprises about 5 to 95 percent by weight of an acrylic adhesive andabout 5 to 95 percent of at least one elastomeric material with atackifying rosin. As described above with reference to the thermoplasticelastomerlacrylic adhesive blends, the elastomer/acrylic adhesives maybe prepared either by solvent blending or by melt blending. Theresulting adhesive may be extruded to obtain an adhesive havingmorphology comprising at least two distinct domains, a first beingsubstantially continuous in nature and the second being fibrillose toschistose in nature in the adhesive forming direction with the firstdomain. Elastomeric materials are materials which generally form onephase at 21° C., have a glass transition temperature less than 0° C. andexhibit elastic properties. Elastomeric materials useful for preparingsuch a blend adhesive include, for example, natural rubbers such asCV-60, a controlled viscosity grade, and SMR-5, a ribbed smoked sheetrubber; butyl rubbers, such as Exxon Butyl 268 available from ExxonChemical Co.; synthetic polyisoprenes such as CARIFLEX™IR309, availablefrom Royal Dutch Shell and NATSYN™ 2210, available from Goodyear Tireand Rubber Co.; ethylene-propylenes; polybutadienes; polyisobutylenessuch as VISTANEX™ MM L-80, available from Exxon Chemical Co.; andstyrene-butadiene random copolymer rubbers such as AMERIPOL™ 1011A,available from BF Goodrich.

These elastomeric materials are modified with tackifying resins, liquidrubbers or plasticizers to lower their melt viscosity to facilitate theformation of fine dispersions, with the smallest phase dimensionpreferably less than about 20 microns when blended with the acrylicpressure-sensitive adhesive. Tackifying resins or plasticizers usefulwith the elastomeric materials are preferably miscible at the molecularlevel, i.e., soluble in, any or all of the polymeric segments of theelastomeric material. The tackifying resins or plasticizers may or maynot be miscible with the acrylic pressure-sensitive adhesive. Thetackifying resin, when present, can generally comprise about 5 to 300parts by weight, more typically about 50 parts to 200 parts by weightbased on 100 parts by weight of the elastomeric material. Theplasticizers, when present, can generally comprise about 5 to 400 partsby weight, typically up to 100 parts, more typically up to 30 parts byweight based on 100 parts by weight of the elastomeric material.

Specific examples of tackifiers useful for preparing anacryliclelastomer blend adhesive include rosins such as FORAL™ 85, astabilized rosin ester from Hercules, Inc., the SNOWTACK™ series of gumrosins from Tenneco, and the AQUATAC series of tall oil rosins fromArizona-Sylvachem; synthetic hydrocarbon resins such as ESCOREZ™ 1310LCaliphatic resin and ESCOREZ™ 2393 aliphatic/aromatic resin, both fromExxon Chemical Co. and WINGTACK™ 95 from Hercules, Inc.; terpene resinssuch as ZONAREZ™ M1115 from Arizona Chemical Co.; and liquid rubberssuch as VISTANEX™ LMMH and VISTANEX™ LMMS, both from Exxon Chemical Co.

Natural rubber pressure-sensitive adhesives may also be used in thepresent invention. Natural rubber pressure-sensitive adhesives generallycontain masticated natural rubber, from 25 parts to 300 parts of one ormore tackifying resins to 100 parts of natural rubber, and typicallyfrom 0.5 to 2.0 parts of one or more antioxidants. The natural rubbermay range in grade from a light pale crepe grade to a darker ribbedsmoked sheet. Tackifying resins typically included in such an adhesiveinclude wood rosin and its hydrogenated derivatives; terpene resins ofvarious softening points, and petroleum-based resins, such as, theESCOREZ™ 1300 series of C5 aliphatic olefin-derived resins from Exxon.Antioxidants are often used to retard the oxidative attack on thenatural rubber that causes natural rubber pressure-sensitive adhesivesto loss their cohesive strength. They include amines, such asN-N'-di-β-naphthyl-1,4-phenylenediamine, phenolics, such as 2,5-di-(tertamyl) hydroquinone, tetrakis[methylene3-(3',5'di-tert-butyl-4'-hydroxyphenyl)propionate]methane, available asIRGANOX™ 1010 from Ciba-Geigy Corp., and2-2'-methylenebis(4-methyl-6-tert-butyl phenol), and dithiocarbamates,such as zinc dithiodibutyl carbamate. Other materials can be added forspecial purposes, including plasticizers, pigments, and curing agents tovulcanize the adhesive partially.

Synthetic rubber pressure-sensitive adhesives may also be used in thepresent invention. These are generally rubbery elastomers which areeither self-tacky or require tackifiers, that can be used as eitherpressure-sensitive adhesives or as tackifiers and modifiers to otherpressure-sensitive adhesives. The self-tacky synthetic rubberpressure-sensitive adhesives comprise either butyl rubber, a copolymerof isobutylene with less than 3 percent isoprene, polyisobutylene, ahomopolymer of isoprene, polybutadiene, or styrene butadiene rubber.Butyl rubber pressure-sensitive adhesives often contain from 0.5 to 2.0parts per 100 parts butyl rubber pressure-sensitive adhesive of anantioxidant such as zinc dibutyl dithiocarbamate. Polyisobutylenepressure-sensitive adhesives do not usually contain antioxidants. Thesynthetic rubber pressure-sensitive adhesives, which generally requiretackifiers, are also generally easier to process. They comprisepolybutadiene or styrenelbutadiene rubber, from 10 parts to 100 parts ofa tackifier, and generally from 0.5 to 2.0 parts per 100 parts rubber ofan antioxidant such as IRGANOX™ 1010. An example of a synthetic rubberis AMERIPOL™ 1011A, a styrene/butadiene rubber available from BFGoodrich. Tackifiers which are useful include derivatives of rosins suchas FORAL™ 85, a stabilized rosin ester from Hercules, Inc., theSNOWTACK™ series of gum rosins from Tenneco, and the AQUATAC™ series oftall oil rosins from Arizona-Sylvachem; and synthetic hydrocarbon resinssuch as the PICCOLYTE™ A series, polyterpenes from Hercules, Inc., andthe ESCOREZ™ 1300 series of C5 aliphatic olefin-derived resins. As withmost adhesives, other materials can be added for special purposes,including hydrogenated butyl rubber, pigments, and curing agents tovulcanize the adhesive partially.

Yet another class of pressure sensitive adhesives useful for the presentinvention include block copolymer pressure sensitive adhesives whichgenerally comprise elastomers of the A-B or A-B-A type, where Arepresents a thermoplastic polystyrene block and B represents a rubberyblock of polyisoprene, polybutadiene, or poly(ethylene/butylene), andresins. Examples of the various block copolymers useful in blockcopolymer pressure-sensitive adhesives include linear, radial, star andtapered styrene-isoprene block copolymers such as KRATON™ D1107P,available from Shell Chemical Co., and EUROPRENE™ SOL TE 9110, availablefrom EniChem Elastomers Americas, Inc.; linearstyrene-(ethylene-butylene) block copolymers such as KRATON™ G1657,available from Shell Chemical Co.; linear styrene-ethylene-propylene)block copolymers such as KRATON™ G1750X, available from Shell ChemicalCo.; and linear, radial, and star styrene-butadiene block copolymerssuch as KRATON™ D1118X, available from Shell Chemical Co., andEUROPRENE™ SOL TE 6205, available from EniChem Elastomers Americas, Inc.The polystyrene blocks tend to form domains in the shape of spheroids,cylinders, or plates that causes the block copolymer pressure-sensitiveadhesives to have two phase structures. Resins that associate with therubber phase generally develop tack in the pressure-sensitive adhesive.Examples of rubber phase associating resins include aliphaticolefin-derived resins, such as the ESCOREZ™ 1300 series and theWINGTACK™ series, available from Goodyear; rosin esters, such as theFORAL™ series and the STAYBELITE™ Ester 10, both available fromHercules, Inc.; hydrogenated hydrocarbons, such as the ESCOREZ™ 5000series, available from Exxon; polyterpenes, such as the PICCOLYTE™ Aseries; and terpene phenolic resins derived from petroleum or terpentinesources, such as PICCOFYN™ A100, available from Hercules, Inc. Resinsthat associate with the thermoplastic phase tend to stiffen thepressure-sensitive adhesive. Thermoplastic phase-associating resinsinclude polyaromatics, such as the PICCO™ 6000 series of aromatichydrocarbon resins, available from Hercules, Inc.; coumarone-indeneresins, such as the CUMAR™ series, available from Neville; and otherhigh-solubility parameter resins derived from coal tar or petroleum andhaving softening points above about 85° C., such as the AMOCO™ 18 seriesof alphamethyl styrene resins, available from Amoco, PICCOVAR™ 130 alkylaromatic polyindene resin, available from Hercules, Inc., and thePICCOTEX™ series of alphamethyl styrenessnys toluene resins, availablefrom Hercules. Other materials can be added for special purposes,including rubber phase plasticizing hydrocarbon oils, such as, TUFFLO™6056, available from Arco, Polybutene-8 from Chevron, KAYDOL™, availablefrom Witco, and SHELLFLEX™ 371, available from Shell Chemical Co.;pigments; antioxidants, such as IRGANOX™ 1010 and IRGANOX™ 10763, bothavailable from Ciba-Geigy Corp., BUTAZATE™, available from UniroyalChemical Co., CYANOX™ LDTP, available from American Cyanamide, andBUTASAN™, available from Monsanto Co.; antiozonants, such as NBC, anickel dibutyldithiocarbamate, available from DuPont; and ultravioletlight inhibitors, such as IRGANOX™ 1010 and TINUVIN™ P, available fromCiba-Geigy Corp.

Another class of pressure sensitive adhesives useful in the inventioninclude silicone pressure sensitive adhesives. Silicone pressuresensitive adhesives generally comprise two major components, a polymeror gum, and a tackifying resin. The polymer is typically a highmolecular weight polydimethylsiloxane or polydimethyldiphenylsiloxane,that contains residual silanol functionality (SiOH) on the ends of thepolymer chain, or a block copolymer comprising lower molecular weightpolydimethylsiloxane or polydimethyldiphenylsiloxane segments connectedby diurea linkages. The tackifying resin is generally athree-dimensional silicate structure that is endcapped withtrimethylsiloxy groups (OSiMe₃) and also contains some residual silanolfunctionality. Examples of tackifying resins include SARTOMER™ 545, fromGeneral Electric Co., Silicone Resins Division, Waterford, N.Y., andMQD-32-2 from Shin-Etsu Silicones of America, Inc., Torrance, Calif.Manufacture of typical silicone pressure-sensitive adhesives isdescribed in U.S. Pat. No. 2,736,721 (Dexter). Manufacture of siliconeurea block copolymer pressure-sensitive adhesive is described in U.S.Pat. No. 5,214,119 (Leir, et al). As identified with other classes ofpressure-sensitive adhesives, other materials can be added to thesilicone pressure-sensitive adhesives, including, but not limited topigments, plasticizers, and fillers. Fillers are typically used inamounts from 0 parts to 10 parts per 100 parts of siliconepressure-sensitive adhesive. Examples of fillers that can be usedinclude zinc oxide, silica, carbon black, pigments, metal powders andcalcium carbonate.

As described in each class of pressure-sensitive adhesives above,tackifiers, plasticizers and fillers are optionally included in pressuresensitive adhesives used for the present invention. These components areadded to design the adhesive so that it is particularly suited for itsintended use. Tackifiers can be included such as hydrocarbon resins,rosin, natural resins such as dimerized or hydrogenated balsams andesterified abietic acids, polyterpenes, terpene phenolics,phenol-formaldehyde resins, and rosin esters. Other additives such asamorphous polypropylene or various waxes may also be used. Plasticizerssuch as polybutene, paraffinic oils, petrolatum, and certain phthalateswith long aliphatic side chains such as ditridecyl phthalate may beadded to the adhesives used in the invention. Pigments and fillers mayalso be incorporated into the adhesive composition in order tomanipulate the properties of the adhesive according to its intended use.For instance, very fine pigments increase cohesive strength andstiffness, reduce cold flow, and also reduce tack. Plate-like pigmentssuch as mica, graphite, and talc are preferred for acid and chemicalresistance and low gas permeability. Coarser pigments increase tack.Zinc oxide increases tack and cohesive strength. Aluminum hydrate,lithopone, whiting, and the coarser carbon blacks such as thermal blacksalso increase tack with moderate increase in cohesivity. Clays, hydratedsilicas, calcium silicates, silico-aluminates, and the fine furnace andthermal blacks increase cohesive strength and stiffness. Finally,antioxidants may be used to protect against severe environmental agingcaused by ultraviolet light or heat One skilled in the art willrecognize that certain situations call for special types ofplasticizers, tackifiers, pigments, fillers and/or antioxidants andselection can be critical to the performance of the adhesive.

Low Adhesion Backsize (LAB)

The invention may optionally include a layer of low adhesion backsize.The LABs may include, for example, waxes such as polyethylene andolcamide; silicones such as diorganopolysiloxanes; and long chainedbranched polymers such as polyvinylstearate, polyvinylcarbamates andfluorocarbon copolymers. However, a feature of the invention is that itprovides a tape construction which does not require low adhesionbacksize in order to achieve easy unwind from a roll of tape if theappropriate combination of adhesives and composite backing is employed.If the polymer is polyethylene-based and the adhesive is either anacrylic/thermoplastic elastomer blend or an acrylic/elastomer blend withor without tackifiers, plasticizers or fillers, a LAB is not necessary.By easy unwind it is meant that the adhesive releases from the clothside of the tape without requiring undue force and without the adhesivepulling away from the polymer side of the backing. Manufacturing costsare reduced in tape constructions of the invention since an additionalmaterial, the low adhesion backsize, is not necessary in order toprovide a useful pressure sensitive adhesive tape having good unwindproperties.

EXAMPLES

The invention is further explained by the following examples which areintended as nonlimiting. Unless otherwise indicated all parts andpercents are expressed in parts by weight.

Unless otherwise indicated the following test methods were used in theExamples.

Tear

Samples were grasped between the index finger and the thumb of bothhands and torn in the cross direction of the sample. The tear line wasexamined for fraying and/or delamination of the polymer from the cloth.The amount of force required to initiate the tear was also considered.The specimen was then tested in a similar fashion in the machinedirection with the same observations noted. If minimal fraying and nodelamination was observed in the sample, and relatively low forces wereneeded to initiate and propagate the tear across the sample, the sampledemonstrated acceptable tear properties. If delamination, fraying, orlarge forces were necessary to initiate and propagate the tear thesample had unacceptable or poor tear properties. This procedure wasrepeated for the down-web direction. For both the web direction andcross-web direction tears, the tear was rated as:

1 Very poor tear with excessive fraying and delamination. Arepresentative tear designated as "1" is shown in FIG. 8.

2 Poor tear with large amount of fraying and delamination.

3 Average tear with some fraying and little delamination. Arepresentative tear designated as "3" is shown in FIG. 9.

4 Good tear with minimal fraying and no delamination.

5 Excellent tear with no fraying or delamination. A representative teardesignated as "5" is shown in FIG. 10.

Tapes or backings prepared according to the invention exhibit tears of 4or 5 when torn by hand and the tear line is substantially straight.

Tensile Measurements

Tensile strength at break, elongation at break and modulus of anextruded film, adhesive tape and/or fabric in the machine or crossdirection, either wet or dry was determined in the following manner. A10.2 cm long by 2.5 cm wide sample was placed between the InstronTensile tester jaws to expose a 5.1 cm gauge length. The crosshead andchart speeds were set at 25.4 centimeters per minute. The jaws weredrawn apart at 25.4 cm/min until a break was detected by the machine.Tensile, elongation, and Fn Modulus(force required to elongate a samplen percent) were calculated via the Instron software.

Adhesion To Steel

Adhesion to steel was determined without any sample dwell on the steelaccording to this procedure. This test standard is based on the ATSMD1000 Adhesion Test.

Tape samples were cut into 2.5 cm by 30.5 cm strips. The samples wereadhered to the center of a cleaned steel surface (cleaned with 50%n-heptane/50% isopropyl alcohol) adhesive side down, so that 12.7 to17.8 cm of sample extended beyond the steel surface. The tape was rolledonce in each direction with a 2.0 Kg roller at a rate approximately 5.1cm per second. The free end of the sample was then doubled back onitself and approximately 2.5 cm was peeled from the steel plate. The endof the panel from which the specimen had been removed was placed in thelower jaw of the tester. The free end was folded to form a small tab andwas placed in the upper jar as above. The specimen was mechanicallyremoved from the plate by activating the Instron at a crosshead speed of30.5 cm per minute and data was recorded on the computer software. Theaverage of three peel values were reported in ounces per inch andconverted to the units of Newtons/decimeter.

Adhesive Adhesion to Composite Backing (2 Bond)

A strip of the sample was placed on the panel as described above so thatthe sample extended 2.5 cm beyond each end of the panel. With the rollerdescribed above, the sample was rolled once in each direction at a rateof 5.1 cm per second. Another strip of sample was applied with theadhesive covering the backside of the first. This was rolled once ineach direction with a 2.0 Kg roller at a rate of approximately 5.1 cmper second. The free end of the sample was then doubled back on itselfand approximately 2.5 cm was peeled from the initial bonded specimen.The end of the panel from which the sample was removed was placed in thelower jaw of the tester. The free end was folded to form a small tab andwas placed in the upper jaw as above. The sample was mechanicallyremoved from the specimen by activating the Instron at a crosshead speedof 30.48 cm per minute and data was recorded on the computer software.The average of three peel values were reported in the units ofounces/inch and converted to Newtons/decimeter.

Hand or Flexibility

The following procedure describes the method of determining the "hand"drape or flexibility of composite materials(nonwovens, wovens, etc,)using the Thwing-Albert Handle-O-Meter.

Samples were cut into squares having measurements such as 20.3×20.3 cmor 10.2×10.2 cm. The web and cross-web direction of the samples wasmarked on each sample. Areas containing wrinkles or creases were avoidedwhen preparing the specimens. The slot width on the Thwing-AlbertHandle--Meter was set to 0.6 cm and a specimen was placed under theblade with the web direction perpendicular to the slot. The directiontested was always perpendicular to the slot. The apparatus was activatedcausing the platform to rise and engage the specimen and forced thespecimen into the slot opening. The platform motion stopped when thetest cycle was completed and displayed the maximum resistance force ofthe blade encountered while pushing the sample through the slot. Theprocedure was then repeated by putting the cross-web directionperpendicular to the slot. The sample was rotated 90 degrees and bothsides of the specimen were measured, thus two values were obtained forboth the web direction and the cross-web direction. The values wereaveraged to obtain the web direction and the cross-web directionmeasurements. Generally, as drape or hand measurements decrease thesample is more conformable.

Unwind Adhesion

This procedure was used to measure the force necessary to unwind tapefrom a roll. An Instron tensile tester was modified by removing thebottom grip of the sample holder and equipping it with an unwind fixturethat resembles a spindle. A 2.5 cm wide finished roll of the tape wasplaced on the fixture and approximately a 10.2 cm piece of tape wasunwound from the roll. A tab was formed at the end. The tab was placedin the upper grip of the Instron so the gauge length was approximately5.1 cm. The crosshead was started in motion at a rate of 30.5 cm perminute and unwound at least 15.2 cm from the roll. The average unwindadhesion was recorded by the Instron software and was reported as anaverage in ounces per inch and converted to Newtons/decimeter. Theunwound portion of the tape was also examined for adhesive transfer,delamination, or tearing.

Moisture Vapor Transmission of Materials

The moisture vapor transmission rates of the samples were tested usingeither the upright method or the inverted method as described below.

Upright method: Glass bottles were filled with approximately 50 ml ofwater. Three test samples and three control samples were cut into 3.8 cmdiameter samples using a round die cutter. The samples were sandwichedbetween two foil rings which had holes in the centers. A rubber gasketwas placed between the bottom of the foil and the glass container. Ascrew cap with a 3.8 cm diameter hole was attached to the glass jarenclosing the foil-sample sandwich and gasket to the glass. The sampleswere conditioned for four hours at 40 degrees C at 20% humidity in acontrol chamber. The cap was then tightly secured to the jar and the jarwas removed from the chamber and weighed on an analytical balance to thenearest 0.01 gram. The jars were returned to the chamber for at least 18hrs (at the conditions listed above). The bottles were then removed andweighed immediately to the 0.01 gram. Moisture vapor rates werecalculated by the change in weight multiplied by the exposed areadivided by the time they were exposed. Rates are reported in grams persquare meter in 24 hours.

Inverted method: The same procedure was followed as outlined above.However, after conditioning the samples in the chamber and weighing, thesamples were returned to the chamber and the bottles were inverted sothat the water contacted the test surface. The bottles were leftundisturbed for at least 18 hrs. The bottles were then removed, weighed,and moisture vapor transmission rate was calculated as above.

Two Bond: Anchorage, Bond

This procedure was used to measure the force necessary to remove apressure sensitive adhesive coating from its backing using masking tapemanufactured by 3M Company as Tape No. 254 as a test tape. Samples werecut into 2.5 cm wide×30.5 cm long strips. Using a clean steel plate, a2.5 cm wide strip of double coated tape (3M Brand Double Stick Tapeavailable from 3M of St. Paul, Minn.) without liner was centered andattached to the plate. The specimen tape was superimposed on the doublecoated tape exposing the adhesive side of the tape. A 30.5 cm strip oftest tape was then centered on the specimen, bonding the adhesive of thespecimen to the adhesive of the standard test tape. The construction wasthen rolled at 228.6 cm per minute with the 2.0 Kg roller. A tab wasformed with the standard test tape, attached to the jaw, and thecarriage was started in motion (approximately 127.0 cm per minute). Thecarriage moved the construction while the jaw held the test tape. Theforce required to remove the adhesive was reported in ounces/inch andconverted to Newtons/decimeter and observations of any failures thatmight have occurred were made. Examples of failures include splitting,transfer, or backing delamination from the double coated tape werenoted.

5 Bond

The following procedure was used to measure the cohesive strength of theadhesive using a 1,750 gram static load. Six samples were cut into 1.3cm wide by 15.2 cm long specimen strips. The end of the strips wereattached in a 1.3 cm ×1.3 cm area bonding adhesive to adhesive. Theother ends were wound around brass hooks. One hook was attached to astationary peg while the other was attached to a 1,750 gram weight. Whenthe samples debonded from one another, the weight fell activating ashut-off timer. The average of three samples was reported in minutes todebond.

Web Porosity

This procedure was used to measure the porosity of backing materials bymeasuring the time required for a volume of 10 cc of air under constantpressure to pass through a known area of sample. Samples were cut into5.1 cm×5.1 cm squares. Using a Gurley Densometer, samples were insertedinto the orifice plates and clamped. The spring catch was disengagedlowering the inner cylinder to settle under its own weight. The time forthe top edge of the cylinder to reach the ZERO line was recorded whichwas the time it took 10 cc of air to pass through the sample as measuredin seconds. If the cylinder did not move after 5 minutes, a value of 301seconds was recorded. As sample materials increase in porosity, the timeinterval decreases. The average results of three samples was reported.

Delamination

To determine if the polymer pulled away from the woven cloth in apolymer/cloth backing, the polymeric film was grasped and pulled atabout a 40 degree angle across the polymer/cloth backing. If the filmcan be lifted away from the cloth without significant deformation of thepolymer or of the cloth, the sample is said to delaminate.

Curl

Samples were torn. The torn edges were examined to determine if theycurled or not. Strong curling is considered undesirable for tapes of theinvention.

Skin Adhesion

Skin adhesion was carried out by placing tape samples 2.5 cm wide by 7.5cm long on the back of a human subject. Each tape was rolled down withone forward and one reverse pass using a 2.0 Kg roller moved at a rateof about 30.0 cm/min. Adhesion to the skin was measured as the peelforce required to remove the tape at 180 degree angle at a 15.0 cm/min.rate of removal. Adhesion was measured immediately after initialapplication (T₀) and after 48 hours (T₄₈). Preferred skin adhesivesgenerally exhibit a T₀ of between about 1.2 to 3.9 N/dm and a T₄₈ ofbetween about 5.8 to 11.6 N/dm. Results of 9 tests were averaged.

Skin Adhesion Lift Test

When the 24 hour skin adhesion test was performed, the tape sample wasexamined for the amount of area that was lifted (released) from the skinprior to removal of the tape and ratings were given as:

    ______________________________________                                        0            no visible lift                                                    1 lift only at edges of tape                                                  2 lift over 1% to 25% of test area                                            3 lift over 25% to 25% of test area                                           4 lift over 50% to 75% of test area                                           5 lift over 75% to 100% of test area                                        ______________________________________                                    

Results of 9 tests were averaged. Preferred skin adhesives willgenerally exhibit an average rating below about 2.5.

Skin Residue Test

When the 24 hour skin adhesion test was performed, the skin underlyingthe tape sample was visually inspected to determine the amount ofadhesive residue on the skin surface and was rated as:

    ______________________________________                                        0          no visible residue                                                   1 residue only at edges of tape                                               2 residue covering 1% to 25% of test area                                     3 residue covering 25% to 50% of test area                                    4 residue covering 50% to 75% of test area                                    5 residue covering 75% to 100% of test area                                 ______________________________________                                    

Results of 9 tests were averaged. Preferred skin adhesives willgenerally exhibit an average rating below 2.5.

Moist Skin Adhesion Test

Human subjects were placed in a controlled environment room where thetemperature was maintained at a constant 32° C. and 30% relativehumidity for 30 minutes to induce perspiration. If after 20 minutes thepanelists had not begun to perspire, they were offered hot drinks tofurther induce perspiration. Skin adhesions were carried out by placing2.5 cm wide by 7.5 cm long on the panelists perspirated back. Each tapewas rolled down with one forward and one reverse pass using a 2.0 Kgroller moved at a rate of about 30.0 cm/min. Adhesion to skin wasmeasured as a peel force required to remove the tape at a 180 degreeangle at a 15.0 cm/min. Adhesion was measured immediately after theinitial application (T₀) Results of 10 tests were recorded as g/in.,averaged and converted to Newtons/dm.

Example 1

Example 1 illustrates varying cloth weave densities and varying filmthicknesses are useful in the present invention.

Films having a thickness of 62.5 microns (2.5 mils), 125 microns (5.0mils) and 225 microns (9.0 mils) were prepared using a polyolefinelastomer based on a copolymer of ethylene and 1-octene with a melt flowindex of 5 dg/min. These films were hot pressed to grade 80 woven cottoncheese cloth (Burcott Mills of Chicago, Ill.) using a Carver platenpress at 180 degrees C and 1362 Kg pressure. The various thread countsused for the samples are shown in Table 1 below. The total thickness ofthe resulting polymer film/cloth composites were between 200-250microns. Tensile measurements were completed on the polymer films, wovencloths and composites generated by the combination of the two. Tensilemeasurements were also completed on Zonas Porous Brand adhesive tapeavailable from Johnson & Johnson Medical, Inc. of Arlington, Tex. as acontrol. Tables 1-3 show tensile results.

                  TABLE 1                                                         ______________________________________                                        Cloth Tensile                                                                   Thread Count  Direction                                                                              Load @ Break (Newtons)                               ______________________________________                                        20 × 12                                                                             DOWN     44                                                         20 × 12 CROSS 2                                                         28 × 24 DOWN 36                                                         28 × 24 CROSS 25                                                        32 × 28 DOWN 79                                                         32 × 28 CROSS 63                                                        40 × 32 DOWN 105                                                        40 × 32 CROSS 52                                                        44 × 36 DOWN 101                                                        44 × 36 CROSS 82                                                        66 × 42 DOWN 167                                                        66 × 42 CROSS 87                                                      ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Film Tensile                                                                       Polymer Thicknesses                                                                         Load @ Break (Newtons)                                     ______________________________________                                         62.5 mil down 14                                                                62.5 mil cross 7                                                             125.0 mil down 18                                                             125.0 mil cross 15                                                            225.0 mil down 31                                                             225.0 mil cross 30                                                          ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        Cloth/Polymer                                                                   Composite Tensile                                                             Polymer Thickness(microns)/Cloth                                                                            Load @ Break                                    Thread Count per 2.54 cm Direction (Newtons)                                ______________________________________                                        62.5/20 × 12 DOWN     51                                                  62.5/20 × 12 CROSS  8                                                   62.5/28 × 24 DOWN 59                                                    62.5/28 × 24 CROSS 32                                                   62.5/32 × 28 DOWN 58                                                    62.5/32 × 28 CROSS --                                                   62.5/40 × 32 DOWN 110                                                   62.5/40 × 32 CROSS 22                                                   62.5/44 × 36 DOWN 153                                                   62.5/44 × 36 CROSS --                                                   62.5/66 × 42 DOWN 179                                                   62.5/66 × 42 CROSS 99                                                   125.0/40 × 32  DOWN 127                                                 125.0/40 × 32  CROSS 18                                                 225.0/40 × 32  DOWN 116                                                 225.0/40 × 32  CROSS 27                                                 Zonas Porous Brand Tape DOWN 167                                            ______________________________________                                    

The cloth and polymer were very difficult to tear alone. The clothrequired a large amount of force to tear, and upon tearing the clothfrayed and became unusable. The polymer tore relatively easily once thetear was initiated, however, it was not clean or straight. By combiningthese two materials at low thread counts acceptable tensile and tearproperties were achieved.

All of the above cloth weaves were not hand tearable in the cross-webdirection without excessive fraying as exemplified in FIG. 8. However,once the low density weave cloths were formed into composites with apolymer the samples were hand tearable in the cross direction. Thecomposite samples all showed good bonding of the polymer to the cloth,good tensile strength in both directions, 45 degree bias and straightline tearing in the cross and down-web directions.

In summary, the tensile properties of the cloth and composites showsimilar trends. As the thread count of the cloth increases, thetensile(load at break) of the materials also increases. In the case ofthe polymer, changes were seen when different thicknesses were used. Thepurpose of the polymer layer is two-fold, it serves as a barrier layerfor the adhesive and more importantly, it binds the crossover points ofthe cloth to provide good tear properties in both directions.

Example 2

Example 2 illustrates that different polymers are useful in preparingcomposite backings of the present invention.

Polymeric materials as identified in Table 4 below were extrusion coatedonto 44×36 threads per 2.5 cm cotton cheese cloth (available fromDeRoyale Textiles of South Carolina supplied through Burcott Mills ofChicago, Ill.). Films were extrusion coated onto the cloth using a 4.4cm Killion single screw extruder equipped with a 25.4 cm Cloeren die,and Rotary Automation film take-away system. After the polymer wasextruded onto the cloth, the polymer/cloth composite was nipped betweena chrome cast roll and nip roll at 4.5 N per lineal centimeter attemperatures ranging from 35-70 degrees C. The polymeric films and theprocessing conditions are listed in Table 4 below.

                                      TABLE 4                                     __________________________________________________________________________    Composites Containing different polymers                                                             Polymer        Cast roll                                    Thickness Thread Ext. Temp Temp Line Speed                                 Sample #  Polymer Tradename Polymer Type (microns) Count (C) (C)                                                       (m/min.)                           __________________________________________________________________________    2A   Attane 4802(Dow)                                                                         Polyethylene                                                                         75.5-82.5                                                                          44 × 36                                                                      254  70   2.1                                    copolymer                                                                   2B Attane 4802(Dow) Polyethylene 50-62.5 44 × 36 254 70 3.1                                                         copolymer                         2C Attane 4802(Dow) Polyethylene 30-37.5 44 × 36 254 70 4.6                                                         copolymer                         2D Flexomer 1137(Union Polyethylene 62.5 free film 185 70 2.1                  Carbide) copolymer                                                           2E Flexomer 1137(Union Polyethylene 77.5-82.5 44 × 36 185 70 1.7                                                   Carbide) copolymer                 2F Flexomer 1137(Union Polyethylene 47.5-52.5 44 × 36 185 70 2.7                                                   Carbide) copolymer                 2G Flexomer 1137(Union Polyethylene 33.8-38.8 44 × 36 185 70 4.0                                                   Carbide) copolymer                 2H Hytrel 4056 (duPont) Polyester 62.5 free film 190 50 3.1                     elastomer                                                                   21 Hytrel 4056 (duPont) Polyester 62.5 44 × 36 190 50 3.1                                                           elastomer                         2J Hytrel 4056 (duPont) Polyester 72.5-80.0 44 × 36 190 50 2.3                                                      elastomer                         2K Hytrel 4056 (duPont) Polyester 45.0-52.5 44 × 36 190 50 3.4                                                      elastomer                         2L Hytrel 4056 (duPont) Polyester 35.0-37.5 44 × 36 190 50 4.6                                                      elastomer                         2M Flexamer 1138(Union Polyethylene 62.5 free film 204 50 3.1                  Carbide) copolymer                                                           2N Flexomer 1138(Union Polyethylene 77.5-82.5 44 × 36 204 50 2.4                                                   Carbide) copolymer                 2O Flexomer 1138(Union Polyethylene 47.5-52.5 44 × 36 204 50 3.7                                                   Carbide) copolymer                 2P Flexomer 1138(Union Polyethylene 32.5-37.5 44 × 36 204 50 5.5                                                   Carbide) copolymer                 2Q Flexomer 1138 w/1% red Polyethylene 47.5-52.5 44 × 36 204 50                                                  3.7                                   pigment copolymer                                                            2R Kratan 1107 (Shell) Black 67.5-82.5 44 × 36 204 50 5.3                                                           Copolymer                         2S Kratan 1107 (Shell) Block 47.5-57.5 44 × 36 204 50 7.6                                                           Copolymer                         2T Kratan 1107 (Shell) Block 40.0-52.5 44 × 36 204 50 9.1                                                           Copolymer                         2U LLDPE 6806 (Dow) Polyethylene 70.0-77.5 44 × 36 160 38 7.5                                                     2V LLDPE 6806 (Dow) Polyethyle                                               ne 45.0-52.5 44 × 36 160                                                38 11.0                              2W LLDPE 6806 (Dow) Polyethylene 30.0-32.5 44 × 36 160 38 13.7                                                    2X 15% LLDPE 6806/85% Polymer                                                blend 70.0-77.5 44 × 36                                                 204 50 2.6                            Flexomer 1138                                                                2Y 15% LLDPE 6806/85% Polymer blend 45.0-52.5 44 × 36 204 50 4.0                                                   Flexomer 1138                      2Z 15% LLDPE 6806/85% Polymer blend 27.5-32.5 44 × 36 204 50 5.2                                                   Flexomer 1138                      2AA 15% LLDPE 6806/85% Polymer blend 12.5-20.0 44 × 36 204 50 6.1        Flexomer 1138                                                                2BB 30% LLDPE 6806/70% Polymer blend 77.5-82.5 44 × 36 204 50 2.6        Flexomer 1138                                                                2CC 30% LLDPE 6806/70% Polymer blend 47.5-50.0 44 × 36 204 50 4.0        Flexomer 1138                                                                2DD 30% LLDPE 6806/70% Polymer blend 27.5-30.0 44 × 36 204 50 5.2        Flexomer 1138                                                                2EE 45% LLDPE 6806/55% Polymer blend 70.0-77.5 44 × 36 204 50 2.7        Flexomer 1138                                                                2FF 45% LLDPE 6806/55% Polymer blend 47.5-52.5 44 × 36 204 50 4.0        Flexomer 1138                                                                2GG 45% LLDPE 6806/55% Polymer blend 30.0-35.0 44 × 36 226 50 6.1        Flexomer 1138                                                                2HH Escorene LD- Ethylene Vinyl 62.5 free film 226 50 3.1                      312.09(Exxon) Acetate                                                        2II Escorene LD- Ethylene Vinyl 75.0-82.5 44 × 36 226 50 2.5                                                       312.09(Exxon) Acetate                                                        2JJ Escorene LD- Ethylene                                                    Vinyl 47.5-52.5 44 × 36                                                 226 50 4.0                            312.09(Exxon) Acetate                                                        2KK Eecorene LD- Ethylene Vinyl 22.5-25.0 44 × 36 226 50 7.6                                                       312.09(Exxon) Acetate                                                        2LL Elvax 240(duPont)                                                        Ethylene Vinyl 77.5-82.5 44                                                   × 36 182 32 3.8                  Acetate                                                                     2MM Elvax 240(duPont) Ethylene Vinyl 45.0-50.0 44 × 36 182 32 6.2         Acetate                                                                     2NN Elvax 240(duPont) Ethylene Vinyl 25.0-30.0 44 × 36 182 32 9.5         Acetate                                                                     2OO Elvax 40W(duPont) Ethylene Vinyl 72.5-83.0 44 × 36 193 32 4.6         Acetate                                                                     2PP Elvax 40W(duPont) Ethylene Vinyl 47.5-52.5 44 × 36 193 32 6.1         Acetate                                                                     2QQ Elvax 40W(duPont) Ethylene Vinyl 27.5-30.0 44 × 36 193 32                                                    10.1                                   Acetate                                                                     2RR Engage 8200 (Dow) Polyethylene 66.5 44 × 36 204 68 12.8                                                         Elastomer                         2SS Engage 8200 (Dow) Polyethylene 53.0 44 × 36 204 68 16.5                                                         Elastomer                         2TT Engage 8200 (Dow) Polyethylene 24.3 44 × 36 204 68 27.5                                                         Elastomer                       __________________________________________________________________________

The composites prepared in Table 4 were slit to 8.9 cm rolls forpost-extrusion experiments. The composites were subjected to postcalendering to further embed the polymer to the woven substrate. Thecloth/polymer composites was nipped between a plasma coated cast rolland rubber back-up roll at about 162 degrees C at 193 N per lineal cmbetween 0.6 to 2.4 m/min. The samples were tested for tensile strength,elongation, tear, drape, and porosity. Control samples were also tested.The control backing was a non-occlusive, i.e., breathable, woven backingconsisting of 180×48 plain weave acetate taffeta cloth, 75 denier fiberin warp direction, 150 denier fiber in weft direction, available fromMilliken and Co. of Spartanburg, Ga. The cloth was a 70×52 bleached purefinished 100% cotton print cloth available from Burcott Mills ofChicago, Ill. Neither the cloth nor the control were coated withpolymer.

                  TABLE 5                                                         ______________________________________                                        Properties of Different Polymeric Composites                                                              Tear                                                 Tensile Elongation 1 = Poor  Porosity                                        Sample (Newtons) (%) 5 = Good Drape (sec.)                                  ______________________________________                                        2A     157       6        5      210 MD  263.0                                      142 CD                                                                    2B 144 6 5 139 MD  33.8                                                           77 CD                                                                     2C 130 5 5 94 MD 1.8                                                              43 CD                                                                     2E 162 7 5 179 MD  95.7                                                           95 CD                                                                     2F 144 6 5 93 MD 247.7                                                            58 CD                                                                     2G 132 5 5 78 MD 71.0                                                             36 CD                                                                     2I-NPC 119 6 1 90 MD 133.8                                                        34 CD                                                                     2J 136 5 5 113 MD  83.4                                                           67 CD                                                                     2K 123 5 5 60 MD 98.3                                                             32 CD                                                                     2L 126 5 3 51 MD 15.9                                                             26 CD                                                                     2N 146 6 5 142 MD  354.0                                                          74 CD                                                                     2O 137 6 5 86 MD 250.8                                                            42 CD                                                                     2P 121 6 5 45 MD 4.7                                                              19 CD                                                                     2P-NPC 110 6 -- 99 MD 384.4                                                       47 CD                                                                     2Q 137 5 5 86 MD 395.1                                                            47 CD                                                                     2R 114 5 5 41 MD >600                                                             21 CD                                                                     2S 112 5 5 31 MD 466.3                                                            20 CD                                                                     2T 111 5 5 30 MD 480.5                                                            19 CD                                                                     2U 169 6 5 412 MD  10.3                                                           305 CD                                                                    2V 159 5 5 296 MD  0.6                                                            182 CD                                                                    2W 138 5 4 217 MD  0.2                                                            132 CD                                                                    2X 133 7 5 144 MD  335.3                                                          86 CD                                                                     2Y 119 5 4 98 MD 152.6                                                            57 CD                                                                     2Z 126 5 4 65 MD 137.4                                                            31 CD                                                                     2AA 112 5 5 88 MD 126.4                                                           43 CD                                                                     2BB 145 6 5 185 MD  213.1                                                         111 CD                                                                    2CC 133 6 5 108 MD  108.3                                                         50 CD                                                                     2DD 130 6 1 156 MD  152.9                                                         88 CD                                                                     2EE 159 6 5 171 MD  202.1                                                         136 CD                                                                    2FF 146 6 5 127 MD  41.1                                                          70 CD                                                                     2GG 132 6 1 118 MD  42.3                                                          63 CD                                                                     2II 155 6 5 204 MD  150.1                                                         132 CD                                                                    2JJ 149 5 5 123 MD  115.6                                                         68 CD                                                                     2KK 135 5 4 79 MD 0.3                                                             33 CD                                                                     2LL 130 5 4 68 MD 53.5                                                            40 CD                                                                     2LL-NPC 114 5 4 75 MD 108.1                                                       36 CD                                                                     2MM 114 5 5 59 MD 12.4                                                            31 CD                                                                     2NN 117 5 2 65 MD 0.2                                                             32 CD                                                                     2OO 117 5 4-5 50 MD 252.5                                                         28 CD                                                                     2PP 123 5 4-5 44 MD 93.9                                                          25 CD                                                                     2QQ 101 5 3 46 MD 1.57                                                            23 CD                                                                     2RR 124 5 5 83 MD >400                                                            55 CD                                                                     2SS 129 6 5 70 MD >400                                                            47 CD                                                                     2TT 111 5 5 63 MD 53.4                                                            40 CD                                                                     Backing 113 5 3 109 MD  0.6                                                       63 CD                                                                     Cloth  77 4 4 31 MD 0.1                                                           20 CD                                                                   ______________________________________                                         NPL = not post calendared                                                

In summary, trends show that as the polymer thickness decreased, thetensile values also decreased slightly. Porosities were also affected bythe amount of polymer used in the construction. As the polymer decreasesin thickness, the porosity generally increases or decreases in seconds).Polymers such as the Kraton are relatively nonporous at all thicknessessince Kraton is not an oxygen permeable material. Composites in whichthe polymer's thickness is around 25 microns or below usually arerelatively porous. However, at these thicknesses, there is too littlepolymer to bind the crossover points of the cloth and to create abarrier for the adhesive. In that case the composite usually displaysholes which results in relatively porous constructions with lowertensile strengths.

Tear was greatly affected by the amount of polymer in the composites.Generally, most of the composites showed good tear properties if thethickness of the polymer was between 37 and 75 microns. Compositescomprised of polymers at thicknesses below about 37 microns generallydisplay poor tear (See, e.g. samples 2L, 2DD, 2NN, 2QQ ). Finally, thepolymer type and thickness affected the drape or conformability of theconstruction. The polymers at thicknesses of 50 to 75 microns had highdrape or handle-o-meter results. In the examples above, values rangedfrom 400-30. In order to reduce damage to the skin and achieve a softfeel, ranges between 60-30 are desirable. Some of the above samplesdisplayed drape values acceptable for use in tape constructions.

Example 3

Example 3 illustrates that different adhesives are useful in woven clothadhesive tape constructions of the present invention. Additionally,Example 3 illustrates that different methods of coating the adhesive tothe polymer/cloth composite are useful in preparing tape constructionsof the invention.

Backing Preparation

The cloth/polymer composite comprised of ENGAGE™ 8200 (a polyolefinavailable from Dow Plastics Co. of Midland, Mich.) extrusion coated onto44×36 woven cloth (available from Burcott Mills). White backing wasproduced by dry blending 1 part of 50:50 titanium dioxide in low densitypolyethylene (available as PWC00001 from Reed Spectrum, Holden Mass.)with 3 parts ENGAGE™ 8200; forming pigmented pellets by melt mixing theblend in a 40 mm twin screw extruder (available from Berstorff ofCharlotte, N.C.) of 200° C. and extruding and pelletizing the strands;dry blending the pigmented pellets with more unpigmented ENGAGE™ 8200 ina ratio of 1:25; melt mixing the blend and feeding the blend atapproximately 270 g/min into the feed throat of a 6.35 cm diameter DavisStandard Model #N9485 single screw extruder (available from DavisStandard, Paucatuck, Conn.) at 204° C. and extruding a 65.0 micron thickfilm onto the cloth with the cast roll temperatures set at 93° C. toform a laminate; and passing the laminate through the nip of twohorizontal rolls at pressures of 17.7 N per lineal cm (200 pound per in)at approximately 1.1 m/min. This cloth/polymer composite was tested fortear and had excellent tear properties designated as "5."

Acrylic Pressure Sensitive Adhesive Preparation

An acrylic pressure sensitive adhesive (designated hereafter as "acrylicadhesive") was prepared in accordance with U.S. Pat. No. 4,833,179(Young, et al.) in the following manner: A two liter split reactorequipped with condenser, thermowell, nitrogen inlet, stainless steelmotor-driven agitator, and a heating mantle with temperature control wascharged with 750 g deionized water, to which was added 2.5 g of zincoxide and 0.75 g hydrophilic silica (CAB-O-SIL™ EH-5, available fromCabot Corp., of Tuscola, Ill.) and was heated to 55 degrees C whilepurging with nitrogen until the zinc oxide and silica were thoroughlydispersed. At this point, a charge of 480 g isooctyl acrylic, 20 gmethacrylic acid, 2.5 g initiator (VAZO™) 64, available from duPont Co.)and 0.5 g isooctyl thioglycolate chain transfer agent was then added tothe initial aqueous mixture while vigorous agitation (700 rpm) wasmaintained to obtain a good suspension The reaction was continued withnitrogen purging for at least 6 hours, during which time the reactionwas monitored to maintain a reaction temperature of less than 70 degreesC. The resulting pressure-sensitive adhesive was collected andmechanically pressed to at least 90% solids by weight.

3A. Hot Melt Acrylic/Thermoplastic Elastomer (TPE) Adhesive Blends

An adhesive containing a blend of an acrylic adhesive (described above)and thermoplastic elastomcric adhesive was prepared by melt blending theacrylic adhesive with a thermoplastic elastomer adhesive (prepared bypreblending 50 parts thermoplastic elastomeric block copolymer KRATON™D1107P available from Shell Chemical Co. of Houston, Tex., 1.0 partsantioxidant IRGANOX™ 1076, available from Ciba-Geigy of Hawthorne, N.Y.and 50 parts tacking resin ESCOREZ™ 1310 LC available from ExxonChemicals of Houston, Tex.) at ratios shown in the table below by drumunloading the pre-compounded thermoplastic elastomeric adhesive into an8.9 cm diameter screw pin barrel mixer, available from The French OilMill Machinery Co., Piqua, Ohio, with zone temperatures maintainedbetween 106° C. and 144° C. Water was injected at 1 part per 100 partspressure-sensitive adhesive composition as the composition leaves thepin barrel mixer. A gear pump attached to the output end of the pinbarrel mixer by a heated pipe delivered the pressure-sensitive adhesivecomposition to a wipe-film coating die, maintained at a temperature of160° C., at 0.63 Kg(hour/cm die width onto the polymer/cloth compositedescribed above. The backing samples were coated with adhesive atthicknesses of 50, 57 and 64 micrometers and the effect of adhesivecoating weight was examined 3M Brand Cloth Adhesive Tape available from3M of St. Paul, Minn. and Zonas Porous brand tape available from Johnson& Johnson Medical, Inc. of Arlington, Tex. were used as CompetitiveSamples. The resulting tape samples and the competitive tapes weremeasured for adhesion to steel, adhesive adhesion to backing, tensilestrength, porosity and moisture vapor transmission rate as describedabove. Results are shown in Table 6 below:

                                      TABLE 6                                     __________________________________________________________________________         Acrylic/TPE                                                                           Coating Thickness                                                                      Adh to Steel                                                                        Unwind  T0  T48 Lift                                                                             Residue                          Sample # ratio (by weight) (microns) (N/dm) (N/dm) Wet To (N/dm) (N/dm)                                                    (1-5) (1-5)                    __________________________________________________________________________    3A   100/0   50 μm --    --  --  --  --  -- --                               3B 75/25 50 μm 27 -- -- -- -- -- --                                        3C 50/50 50 μm 34 6 2.3 1.5 3.7 1.1 0.3                                    3D 25/75 50 μm 38 5 2.1 2.0 2.2 2.9 0.0                                    3E 20/80 50 μm 38 2 2.2 2.3 1.5 2.9 0.0                                    3F 0/100 50 μm 40 3 1.8 1.5 2.3 3.9 0.4                                    3G 100/0 57 μm -- -- -- -- -- -- --                                        3H 75/25 57 μm 27 -- -- -- -- -- --                                        3I 50/50 57 μm 25 -- -- 1.8 3.4 1.5 0.2                                    3J 25/75 57 μm 38 -- -- 2.0 1.4 3.1 0.0                                    3K 20/80 57 μm 34 -- -- 2.1 2.0 2.6 0.0                                    3L 0/100 57 μm 42 -- -- 1.3 1.1 5.0 0.0                                    3M 100/0 64 μm -- -- -- -- -- -- --                                        3N 75/25 64 μm 32 -- -- -- -- -- --                                        3O 50/50 64 μm 38 -- 2.8 1.8 3.2 2.0 0.3                                   3P 25/75 64 μm 40 -- 2.1 1.9 1.8 3.6 0.0                                   3Q 20/80 64 μm 41 -- 2.1 2.0 2.0 2.4 0.0                                   3R 0/100 64 μm 42 -- 1.7 1.9 2.6 4.0 0.0                                   3M Brand control -- 13 96 3.6 1.2 4.1 1.4 0.8                                 J&J Zonas control -- 12 14 2.2 0.9 3.3 1.8 0.5                                Porous                                                                      __________________________________________________________________________

3B. Solvent Coated Acrylic/Thermoplastic Elastomer Adhesive Blends

An adhesive containing a blend of an acrylic adhesive and thermoplasticelastomeric adhesive was prepared by dissolving the acrylic adhesive(described above) in a heptane/isopropyl alcohol 90/10 mix at 25% solidsin a 3.8 liter glass jar. The thermoplastic elastomer (KRATON™ 1107) wastackified using ESCOREZ™ 1310LC so that a 50:50 ratio was obtained. TheKRATON™/tackifier composition was dissolved in toluene at 50% solids ina 3.8 liter glass jar. Each batch solution was mixed on a roll mixerovernight at room temperature (25 degrees C). Various blend ratios wereprepared by combining the appropriate amounts acrylic adhesive andKRATON™ adhesive in 0.9 liter glass jars, sealed with lids and allowedto mix on a roll mixer overnight at room temperature.

The adhesives were coated on the cloth/polymer composites describedabove varying percent solids to produce coatings with a thickness of 32micrometer. The coating was accomplished with a 25.4 cm wide knifecoater at several different coating gaps depending on the percent solidsof the blends. Processing conditions are shown in Table 7 below.

                  TABLE 7                                                         ______________________________________                                              Acrylic/                                                                   Thermo-                                                                       plastic  Ctg Ctg                                                             Sample Elastomer  Orifice Thickness Speed                                     # ratio % Solids (microns) (micrometer) (m/min.)                            ______________________________________                                        3S     0:100   50.0% solids                                                                            100    32      1.4                                     3T 25:75 43.8% solids 100 32 1.4                                              3U 50:50 37.5% solids 100 32 1.4                                              3V 75:25 31.3% solids 135 32 1.4                                              3W 100:0  25.0% solids 218 32 1.4                                             3X 10:90 47.4% solids 100 32 1.3                                              3Y 90:10 27.5% solids 350 32 1.5                                            ______________________________________                                    

The coated samples were then subjected to a dual oven system to removethe solvent in the adhesives. The first oven temperature was at 37.7degrees C while the second oven was at 135 degrees C. A liner (Daubert)was inserted before wind-up to ensure the adhesives on the samples wouldnot block on the uncoated backing surface before testing was complete.The resulting tape samples were measured for adhesion to steel, adhesiveadhesion to backing, tensile strength, porosity and moisture vaportransmission rate as described above. Additionally, Zonas Porous brandtape available from Johnson & Johnson Medical, Inc. of Arlington, Tex.and 3M brand Cloth Adhesive Tape available from 3M of St. Paul, Minn.were tested for the same properties for comparative purposes. Resultsare shown in Table 8 below:

                                      TABLE 8                                     __________________________________________________________________________          Adhesion to                                                                         Adhesion to                                                                          Tensile   2 Bond                                                                            Porosity                                                                            MVTR   T0   T48                          Sample Steel (N/dm) backing (N/dm) (N) Elongation (N/dm) (seconds)                                                                     .sup.2 /day                                                                   (N/dm) (N/dm)                                                                 Lift Residue       __________________________________________________________________________    3S    14    3      120 N                                                                             4%    --  >300  63 g/m2/day                                                                          1.5  0   5.2 0.3                  3T 12 2 127 N 4% 89 >300 103 g/m2/day 1.8 0 4.7 0.0                           3U 8 4 109 N 4% 61 >300 134 g/m2/day 2.1 2.7 1.5 1.0                          3V 7 3 109 N 4% 35 >300 134 g/m2/day 2.0 3.9 1.5 2.0                          3W 7 5 123 N 4% 9 >300 174 g/m2/day -- -- -- --                               3X 20 8 121 N 5% -- >300 55 g/m2/day 2.8 0.5 4.8 0.0                          3Y 14 7 125 N 4% 37 >300 134 g/m2/day 2.9 5.6 1.1 2.4                         J&J Zonas 12 11 190 N 7% 138 4.8 3784 g/m2/day 1.4 2.0 2.4 0.3                3M Brand 23 35 151 N 5% 125 28.5 830 g/m2/day -- -- -- --                   __________________________________________________________________________

3C Hot Melt Acrylic/Thermoplastic Elastomer/Filler Blend Adhesive

An adhesive containing an acrylic adhesive (described above),thermoplastic elastomeric adhesive, and filler were melt blended in atwin screw extruder fitted with a screw suitable for thermoplasticelastomers and hot melt coated directly onto the cloth/polymer laminate.The blend containing an acrylic adhesive/thermoplasticelastomer/tackifying resin/filler at 60/20/20/11.1 parts respectivelywas prepared by feeding KRATON™ D1107 pellets (Shell Chemical) intoBarrel 1 of a 30 mm ZSK 30 Wemer-Pfleiderer twin screw extruder, addinga tackifier/filler powder mixture of ESCOREZ™ 1310 LC (Exxon Chemical)and alumina trihydrate (Micral 1500 grade from Solex Industries,Norcross, Ga.) at a ratio 1.8:1 into Barrel 3 of the extruder andfeeding the acrylic adhesive (prepared as described above) into Barrel 8of the twin screw extruder. The blend was compounded in the extruder at149 degrees C at rpm of approximately 400, passed through a screenfilter and gear pump located at the end of the extruder at 166 degrees Cand delivered by a heated pipe to a wipe-film coating die maintained at166 degrees C. Extruder outputs were approximately 2.0 Kg/hr/14 cm diewidth. The adhesive coating had an average thickness of approximately 50micrometers.

The 30 mm ZSK 30 Werner-Pfleiderer twin screw extruder with a 45:1 L/Dwas used consisting of 15 barrel section and controlled by 6 zoneheaters. The extruder configuration and processing conditions were asfollows:

    __________________________________________________________________________    Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6                                     __________________________________________________________________________    Barrels 1-3                                                                          Barrels 4-6                                                                          Barrels 7-8                                                                          Barrels 9-10                                                                         Barrels 11-13                                                                        Barrels 14-15                                52 degrees C. 135 degrees C. 149 degrees C. 149 degrees C. 149 degrees                                         C. 149 degrees C.                          __________________________________________________________________________

The samples were tested for their adhesion to steel, adhesion tobacking, unwind, initial adhesion to skin and after 48 hours, lift andresidue. Results are shown in Table 9 below.

                  TABLE 9                                                         ______________________________________                                        Hot Melt Acrylic/TPE Filler Properties                                          Sam-   Adh steel                                                                              Adh backing                                                                           Unwind                                                                              T0   T48                                        ple N/dm N/dm dN/dm N/dm N/dm Lift Residue                                  ______________________________________                                        3C   25       12        9     1.0  3.1  1.0  0.0                              ______________________________________                                    

Example 4

Example 4 demonstrates that adhesives comprised of acrylic adhesive andelastomer blends which are hot melt coated or solvent coated onto thecomposite backing are useful in preparing tapes according to theinvention.

Backing Preparation

The cloth/polymer composite comprised of ENGAGE™ 8200 (a polyolefinavailable from Dow Plastics Co.) was extrusion coated onto 44×36 wovencotton cloth (available from Burcott Mills). White backing was producedby dry blending 1 part of 50:50 titanium dioxide in low densitypolyethylene (available as PWC00001 from Reed Spectrum, Holden Mass.)with 3 parts ENGAGE™ 8200; forming pigmented pellets by melt mixing theblend in a 40 mm twin screw extruder (available from Berstorff) at 200°C. and extruding and pelletizing the strands; dry blending the pigmentedpellets with more unpigmented ENGAGE™ 8200 in a ratio of 1:25; meltmixing the blend and feeding the blend at approximately 270 g/min intothe feed throat of a 6.35 cm diameter Davis Standard Model #N9485 singlescrew extruder (available from Davis Standard, Paucatuck, Conn.) at 204°C. and extruding a 65.0 micron thick film onto the cloth with the castroll temperatures set at 93° C. to form a laminate; and passing thelaminate through the nip of two horizontal rolls at pressures of 350 Nper lineal cm (200 pound per in) at approximately 1.1 m/min. Thecomposite demonstrated excellent tear properties when the hand tear testwas used.

The acrylic adhesive used to prepare the adhesive blends for samples ofExample 4A, 4B and 4C is described in Example 3 above.

4A. Hot Melt Acrylic/Elastomer Adhesive Blends

The acrylic/elastomer adhesive blends were prepared in aWerner-Pfleiderer ZSK 30 mm twin screw extruder with a 37:1 L/D equippedwith a Zenith pump for metering. Samples 4A-4H were prepared by feedingthe elastomer into barrel 2 of the extruder. In barrek 1, the tackifierswere added. Into barrel 6, the acrylic adhesive described above wasadded. Samples 4I-4L were prepared by feeding the elastomeric Vistanex™MML-80 into barrel 2 Vistanex™ LMMH was fed into zone 2 of the extruder.In zone 4, the tackifiers were added into barrel 6, the acrylic adhesivedescribed above was added. Samples 4M-4P were prepared by feeding theelastomer into barrel 2 of the extruder. Into barrel 2, the Ameripol™block copolymer was added. Into barrel 4, the tackifiers were added.Into barrel 6, the acrylic adhesive described above was added.

The adhesive blends were coated onto the backing described above using a14 cm wiping die at web speeds between 6.8-12.8 m/min to achieve thetarget coating thickness of 50 microns. Extruder speeds on the twinscrew extruder were held at 200 rpm. Overall flow rates were kept in the4.9-9.1 kg/hr range.

Process temperatures for the blends were:

                                      TABLE 10                                    __________________________________________________________________________    Sample                                                                            Zone 1 Zone 2 Znne 3 Zone 4 Zone 5 Zone 6 Die                             __________________________________________________________________________    4A-4D                                                                             163 degrees C                                                                        174 degrees C                                                                        175 degrees C                                                                        177 degrees C                                                                        176 degrees C                                                                        177 degrees C                                                                        177 degrees C                     4E-4H 149 degrees C 161 degrees C 163 degrees C 163 degrees C 163                                                         degrees C 163 degrees C 163                                                   degrees C                         4I-4L 149 degrees C 175 degrees C 204 degrees C 204 degrees C 198                                                         degrees C 207 degrees C 204                                                   degrees C                         4M-4P 83 degrees C 89 degrees C 94 degrees C 94 degrees C 94 degrees C                                                    94 degrees C 106 degrees        __________________________________________________________________________                                                  C                           

3M Brand Cloth Adhesive tape was used as a competitive tape. Samples andthe control were tested for adhesion to steel, adhesion to backing,2-Bond, 5-Bond, Initial Adhesion (T₀) and Adhesion after 48 hours (T₄₈)with results shown in Table 11 below.

                                      TABLE 11                                    __________________________________________________________________________         Acrylic/Elastomer                                                                     Adhesion to                                                                         Adhesion to                                                                           2-Bond                                                                              6-Bond                                                                             Wet T0                                                                            To   T48                              Sample ratio Steel (N/dm) backing (N/dm) (% Transfer) (min.) N/dm                                                                      (N/dm) (N/dm)                                                                 Lift Residue                                                                  Unwind             __________________________________________________________________________    4A   0/100.sup.1                                                                           22    13      75%   0.4 min.                                                                           3.4 4.8  3.5 1.4 2.0 --                       transfer                                                                  4B 25/75.sup.1 22 6 100% 0.9 2.3 1.9 1.9 2.8 1.3 --                           4C 50/50.sup.1 33 11 100% 0.4 2.7 3.1 4.8 1.0 2.3 34                          4D 75/25.sup.1 37 9 100% 0.2 3.1 4.1 8.2 0.8 3.7 --                           4E 0/100.sup.2 22 2  75% 0.2 1.6 1.7 1.9 1.2 0.3 61                           4F 25/75.sup.2 48 8  75% 0.2 3.2 3.2 3.4 1.4 1.3 72                           4G 50/50.sup.2 51 11  90% 0.3 3.8 3.5 5.3 1.3 1.8 48                          4H 75/25.sup.2 48 13 100% 0.2 4.4 3.3 6.5 0.6 2.5 34                          4I 0/100.sup.3 35 3 100% 2.9 1.5 1.3 0.0 5.1 0.0 --                           4J 25/75.sup.3 41 5 100% 2.1 1.9 1.8 1.4 2.3 0.1 --                           AK 50/50.sup.3 43 8 100% 0.6 2.6 2.2 2.9 1.4 0.5 59                           4L 75/25.sup.3 40 10 100% 0.3 3.1 2.8 5.4 0.8 1.2 --                          4M 0/100.sup.4 49 5 100% 0.3 3.5 4.0 2.4 2.0 3.0 --                           4N 25/75.sup.4 19 11 100% 0.1 1.7 2.5 3.0 1.2 3.7 --                          4O 50/50.sup.4 22 13 100% 0.1 1.7 2.8 4.6 0.7 3.6 18                          4P 75/25.sup.4 24 13 100% 0.1 2.1 3.8 5.4 1.2 4.6 16                          Control Natural Rubber. 21 NA  35% 5.7 3.8 0.9 4.6 1.1 1.0 14               __________________________________________________________________________     .sup.1 Natsyn ™ 2210(pnlyisoprene), Wingtack ™ 95(tackifier) at 100     parts/70 parts respectively;                                                  .sup.2 Natsyn ™ 2210, Vistanex ™ LMMH(polyisobutylene) at 100           parts/167 parts respectively                                                  .sup.3 Vistanex ™ MML80, Wingtack ™ 95, Vistanex ™ LMMH at 100       parts/32 parts/48 parts respectively.                                         .sup.4 Ameripol ™ 1011A(Styrenebutadiene elastomer),Foral ™             85(tackifier) at 100 parts/100 parts respectively.                       

The data shows that both adhesion to steel and skin can be manipulatedby altering the relative amounts of acrylic adhesive, elastomer andtackifier, as well as the type of elastomer.

4B Solvent Coated Acrylic/Elastomer Blend Adhesive

Composite Backing Preparation

Example 4B demonstrates that acrylic(elastomer adhesive blends which aresolvent coated onto a composite backing are useful in preparing tapesaccording to the invention. The cloth/polymer composite backing used inthis Example was prepared as explained in Example 3 above.

Solvent coated adhesive tape samples were generated in the followingmanner. The solvent borne adhesive blends were prepared by dissolvingthe acrylic adhesive (described above) in a toluene/heptane 90/10 mix at20% solids in a 3.8 liter glass jar. The Natsyn™ 2210/Vistanex™ LMMH(100 parts/167 parts) compositions were dissolved in heptane at 20%solids in a one gallon (3.8 liter) glass jar using a lightening mixerfor 24 hrs. Both master batch solutions were then mixed on a roll mixerfor 24 hrs at room temperature. The various blend ratios were preparedin similar fashion as the master batches. The appropriate amountsacrylic adhesive and elastomer blend at that given adhesive ratio wereweighed in 16 oz. (0.9 liter) glass jars, sealed with lids and allowedto mix on a roll mixer overnight at room temperature (25 degrees C).

                                      TABLE 12                                    __________________________________________________________________________                         Orifice                                                                            Coating     Zone 1                                                                            Zone 2                                                                            Adhesion                                                                           T.sub.0                                                                          T.sub.48                  Sam-  Adhesive (mil) Thickness Speed Temp. Temp. to Steel (N/ (N/  Res-       ple Backing Acrylic/Elastomer ratio (microns) (micrometers) (m/min.)                                                                    (C) (C)                                                                       (N/dm) dm)                                                                    dm) Lift          __________________________________________________________________________                                                                idue              4Q Cloth/Polymer                                                                        100/0 @ 20% solids                                                                       388  50.7   1.1  37  135 --   2.0                                                                              9.5                                                                              0.2                                                                              0.4                 4R Cloth/Polymer 0/100 @ 20% solids 312 50.0 1.1 37 135  9 1.5 1.4 0.7                                                                  0.7                 4S Cloth/Polymer 25/75 @ 20% solids 312 50.0 1.1 37 135 28 2.0 2.8 0.8                                                                  0.4                 4T Cloth/Polymer 50/50 @ 20% solids 388 51.8 1.1 37 135 23 2.0 6.0 0.7                                                                  0.5                 4U Cloth/Polymer 75/25 @ 20% solids 380 51.1 1.1 37 135 21 2.2 7.5 0.6                                                                  0.5               __________________________________________________________________________

4C Hot Melt Acrylic/Elastomer/Filler

An adhesive containing an acrylic pressure sensitive adhesive,elastomeric adhesive and filler were melt blended in a twin screwextruder and hot melt coated directly onto the cloth/polymer laminate.The blend containing the acrylic/elastomer/tackifying resin/Zincoxide/Alumina trihydrate at 50/18.75/31.25/2/10 parts respectively wasprepared by feeding NATSYN™ 2210 pellets (Goodyear Tire and RubberCompany) into barrel 1 of a 30 mm Werner-Pfleiderer twin screw extruder(45:1 L:D) adding a premix of the Zinc oxide(KADOX™ 911C, from ZincCorporation of America, Monaca, Pa.)/Alumina trihydrate (Micral 1500grade from Solex Industries, Norcross, Ga.) into barrel 3, adding theVISTANEX™ LMMH into barrel 5 of the extruder and feeding the acrylicadhesive into barrel 8 of the twin screw extruder. The blend wascompounded in the extruder at 149 degrees C at rpm of approximately 425,passed through a screen filter and gear pump located at the end of theextruder at 166 degrees C and delivered by a heated pipe to a wipe-filmcoating die maintained at 166 degrees C. Extruder outputs wereapproximately 2.0 kg/hr/14 cm die width. The adhesive coating had anaverage thickness of approximately 50 μm (2 mils).

Process Conditions for Sample 4V were as follows:

    __________________________________________________________________________    Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6                                     __________________________________________________________________________    Barrels 1-3                                                                          Barrels 4-6                                                                          Barrels 7-8                                                                          Barrels 9-10                                                                         Barrels 11-13                                                                        Barrels 14-15                                52 degrees C. 135 degrees C. 149 degrees C. 149 degrees C. 149 degrees                                         C. 166 degrees C.                          __________________________________________________________________________

Sample 4V was tested for adhesion properties and results are shown inTable 13 below.

                  TABLE 13                                                        ______________________________________                                              Adh steel                                                                              Adh back Unwind                                                                              TO   T48                                          Sample N/dm N/dm N/dm N/dm N/dm Lift Residue                                ______________________________________                                        4V    5.9      4.0      13.3  2.1  3.8  0.8  0.2                                ZONAS 13.0 15.6 14.3 1.9 3.7 1.2 0.1                                          Porous                                                                      ______________________________________                                    

Example 5

Example 5 illustrates that tape constructions of the invention can beembossed to improve porosity and moisture vapor transmission rateswithout unduly decreasing adhesion of the tape to steel or skin.

Samples generated in Example 3B above was embossed in order to perforatethe tape. Five foot sections of each sample was placed on a releaseliner and run through a calender stack at 90.5 degrees C under 120 pli(210 N per lineal cm) at 9.45 m/min. using a roller having a raisedsquare pyramidal pattern with 97 holes per square centimeter. 3M BrandCloth Adhesive tape and Zonas Porous Brand tape were used as controltapes. The perforated samples and control tapes were then tested foradhesion to steel, adhesion to backing, tensile strength, elongation,2-Bond, porosity and moisture vapor transmission rate with results shownin Table 14 below.

                                      TABLE 14                                    __________________________________________________________________________    Physical properties of embossed sample.                                                  Adh to                                                                Adh to Steel backing Tensile  2 Bond Porosity MVTR                           Sample (N/dm) (N/dm) (N) Elongation (N/dm) (sec.) (g/m                                                        .sup.2 /day)                                __________________________________________________________________________    5-3S 4     2    125  5%   11  0.4 5135                                          5-3T 5 2 122 5% 47 0.6 4487                                                   5-3U 25 5 155 5% -- 92.3 181                                                  5-3V 7 1 66 5% 67 2.4 2994                                                    5-3W 5 2 124 5% -- 2.3 3028                                                   5-3X 8 3 122 5% 51 0.6 4764                                                   5-3Y 12 4 114 4% -- 3.0 2718                                                  5-4A 12 30 125 5% 79 3.0 2451                                                 5-4B 1 3 128 5% NA 3.0 3029                                                   5-4C 16 4 128 5% NA 3.0 1888                                                  5-4D 14 3 101 4% NA 1.0 2813                                                  5-4E 7 2 115 6% NA 20.0 2135                                                  5-4F 16 2 119 6% NA 6.0 956                                                   5-4G 28 3 121 5% NA 3.0 2552                                                  5-4H 24 3 117 5% NA 4.0 2120                                                  5-41 13 1 123 6% NA 96.0 979                                                  5-4J 19 1 118 5% NA 5.0 1326                                                  5-4K 18 2 123 5% NA 4.0 2050                                                  5-4L 18 2 123 5% NA 3.0 2035                                                  5-4M 16 3 116 5% NA 1.0 3707                                                  5-4N 66 3 118 5% NA 1.0 3453                                                  5-4O 27 3 114 5% 28 1.0 4224                                                  5-4P 27 3 114 6% 28 3.0 2929                                                  Control- 25 36 149 5% 125  37.0 3831                                          3M Brand                                                                      Control 13 1S 156 7% 113  2.0 779                                             J&J Zonas                                                                     Porous                                                                      __________________________________________________________________________

The tape samples showed a decrease in adhesion properties afterembossing. This indicates that the temperature/pressure profiles forembossing affected the overall adhesion of the samples. The possiblecauses include detackification due to polymer degradation, orcontamination from the release liner. In either case, the embossing stepdid not affect the tensile or elongation properties of the backing andenhanced the porosity and MVTR properties as compared to unembossedExample 8B.

Embossing lowered the adhesive properties of the samples withoutaffecting the tensile strength or elongations of the backings.Improvements in the porosity and the moisture vapor transmission rate ofthe overall construction was observed.

Example 6

Example 6 shows that adhesives used to make an embodiment of theinvention can be cross-linked using electron beams.

Composite backings were prepared according to the protocol described inExample 3. The backings were coated with adhesives as described inExample 4A. Some of the samples were embossed as described in Example 5.

Samples which contained elastomer/tackifier pressure-sensitive adhesivescomprised of either Natsyn™ 2210/Wingtack™ 95 (Samples 6A-6E) orAmeripol™/Foral™ 85 (Samples 6F-6J) with respective ratios given in thetable below with and without embossing were irradiated using a Lab UnitElectrocurtain Model # CB175, Serial # 7521 made by Energy Sciences ofWilmington, Mass. Samples were treated at 0, 2, and 4 Mrad at 175 kvusing 1 pass at 3.8 m/min by adhering the samples to a polyester carrierweb with the adhesive side exposed. The samples were irradiated andimmediately contacted with a release liner. Each sample was tested foradhesion of the adhesive to steel, adhesion of the adhesive to backing,down-web direction tensile strength, elongation, 2 bond, porosity, andmoisture vapor transmission rate. Results are shown in Table 15 below.

                                      TABLE 15                                    __________________________________________________________________________          Acrylic/Elastome                                                                      E-beam Dosage/                                                                         Adh to Steel                                                                         Adh to backing                                                                       Tensile   2 Bond                                                                            Porosity                                                                           MVTR                    Sample Ratio Embossing (N/dm) (N/dm) (N) Elongation (N/dm) (sec.)                                                                   (g/m.sup.2            __________________________________________________________________________                                                            /day)                 6A    0/100.sup.1                                                                           2 Mrad   22     10     119  5%   46  >300 53 g/m2/day                                                                      no embossing                                                                6B 0/100.sup.1 4                                                             Mrad 25 14 110 5%                                                             43 >300 45                                                                       no embossing                                                                6C 0/100.sup.1 0                                                             Mrad 17 28 94 5%                                                              81 1.4 2656                                                                      embossed                                                                    6D 0/100.sup.1 2                                                             Mrad 17 23 117 5%                                                             67 1.5 3879                                                                      embossed                                                                    6E 0/100.sup.1 4                                                             Mrad 12 17 109 5%                                                             48 0.9 3830                                                                      embossed                                                                    6F 0/100.sup.2 2                                                             Mrad 33 4 113 8%                                                              42 >300 68                                                                       no embossing                                                                6G 0/100.sup.2 4                                                             Mrad 25 4 95 4%                                                               44 >300 68                                                                       no embossing                                                                6H 0/100.sup.2 0                                                             Mrad 19 3 102 5%                                                              -- 1.4 3551                                                                      embossed                                                                    6I 0/100.sup.2 2                                                             Mrad 21 4 113 5%                                                              -- 1.6 3747                                                                      embossed                                                                    6J 0/100.sup.2 4                                                             Mrad 17 3 94 4%                                                               -- 1.7 3995                                                                      embossed                                                                    Zonas Natural                                                                Rub. NA 12 10 179                                                             8% 112 2.3 3310                                                                Porous                 3M Brand Natural Rub NA 18 34 138 7% 124 106.3 609                          __________________________________________________________________________     .sup.1 Natsyn ™ 2210/Wingtack ™ 95 100 parts Natsyn/70 parts            Wingtack                                                                      .sup.2 Ameripol ™ /Foral ™ 85 100 parts Natsyn/100 parts Wingtack  

Only slight changes in the adhesion to steel and adhesion to backingnumbers were observed after irradiating the samples. These changes arcnot considered critical.

Example 7

Hot Melt Tackified Acrylic

An adhesive containing an acrylic pressure sensitive adhesive (describedin Examples 3 and 4) and tackifying resin were melt blended in a twinscrew extruder and hot melt coated directly onto the cloth/polymerlaminate. The blend containing an acrylic adhesive/tackifying resin at90/10 parts respectively was prepared by feeding acrylic adhesive inbarrel 1 of a 30 mm Wemer-Pfeiderer ZSK 30 twin screw extruder, adding atackifier of ESCOREZ™ 1310 LC (Exxon Chemical) in barrel 1 of theextruder. The blend was compounded in the extruder at 149 degrees C atrpm of approximately 325, passed through a screen filter located andrespective gear pump at 166 degrees C and delivered by a heated pipe toa wipe-film coating die maintained at 166 degrees C. Extruder outputswere approximately 3.6 Kg/hr/14 cm die width. The adhesive coating hadan average thickness of approximately 50 microns (2 mils). The hotmelt/tackified adhesives were tested and results are shown in Table 16below.

                  TABLE 16                                                        ______________________________________                                        Hot Melt Tackified Acrylic Properties                                                                    Adhesion to                                           Adh to steel backing Unwind                                                  Sample (N/dm) (N/dm) (N/dm)                                                 ______________________________________                                        7A      23             23        34                                           ______________________________________                                    

Example 8

This example demonstrates that different adhesives coated from solventare useful in preparing tapes of the invention.

An acrylic-based adhesive containing iso-octylacrylic/acrylicacid/styrene macromer at ratios of 96/2/2 at 50% solids in ethyl acetatewas coated onto cloth/polymer composite samples created in Example 3above. The same procedure and equipment as in Example 3B was used tocoat the adhesive. The processing conditions are listed in Table 17below.

                  TABLE 17                                                        ______________________________________                                        Processing Conditions                                                           Sample          Adhesive                                                                             Coating Coating                                        #  Backing % Solids Orifice Thickness Speed                                 ______________________________________                                        8A    Cloth/  50.0%    125 microns                                                                           42.9    1.8 m/min.                                Polymer solids  micrometer                                                 ______________________________________                                    

The adhesive-coated samples were then tested for adhesion of the tape tosteel, adhesion of the adhesive to backing, web direction tensilestrength, elongation, 2 bond, porosity, and moisture vapor transmissionrate. Results are shown in Table 18 below.

                                      TABLE 18                                    __________________________________________________________________________        Adhesion to                                                                         Adhesion to                                                                          Tensile  2 Bond                                                                            Porosity                                          Sample Steel (N/dm) backing (N/dm) (N) Elongation (N/dm) (sec.)             __________________________________________________________________________                                      MVTR                                        8A  31    7      125 5%   37  >300                                                                              134 g/m2/day                                __________________________________________________________________________

In most cases, the adhesive debonded from the polymer backing whentested against another surface (steel, skin, etc.).

EXAMPLE 9

This example demonstrates that a tape of the invention created bysolvent-coating the adhesive to the cloth\polymer composite backing canbe embossed to improve the moisture vapor transmission rate and toincrease the porosity of the tape.

A five foot section of the sample generated in Example 8 was placed on arelease liner. This sample was then embossed by running the samplethrough a calender stack at 90.5 degrees C under 120 pli at (210 N perlineal cm). The embossed sample had 97 holes/cm² perforated area. Thissample was then tested for its physical properties along with controltapes with the results shown in Table 19 below.

                                      TABLE 19                                    __________________________________________________________________________        Adhesion to                                                                         Adhesion to                                                                          Tensile   2 Bond                                                                            Porosity                                         Sample Steel (N/dm) backing (N/dm) (N) Elongation (N/dm) (min.)             __________________________________________________________________________                                       MVT                                        9A  26    4      113  4%    25 1.1 3871                                         J&J 12 11 190 7% 138 4.8 3784                                                 Zonas                                                                         3M 23 35 151 5% 125 28.5  829                                                 Brand                                                                       __________________________________________________________________________

The same trends occur with these embossed samples as with the samples inExample 5. That is, the adhesion to steel and backing decrease withembossing. However, the tensile properties of the tape did not decrease.The porosity of the tape was improved by embossing holes into thestructure as evidenced by the low porosity value and high moisture vaportransmission rate.

Example 10

Example 10 demonstrates fibrous regularly spaced substrates are usefulfor preparing backings for the tape of the invention.

An approximately 12.7×12.7 cm square piece of CLAF® fabric backingavailable from Amoco Nisseki CLAF Inc. of Atlanta, Ga. was placed on anapproximately 12.7×12.7 square piece of 4 mil thick polymer comprised ofa 10% by weight blend of Kraton 1107 and 90% by weight acrylonitrilebutadiene styrene (ABS) Cycolac™ DFA 1000R available from GeneralElectric of Pittsfield, Mass. The CLAF™ fabric backing and polymer wereplaced between two 25.4×25.4 cm square chrome platen plates each havingan approximate thickness of about 6400 microns. The sandwiched plateswith the backing and polymer in between were then placed into a WabashHeated Flat Platen Press available from Wabash, MPI of Wabash, Ind.which was heated to 143° C. The plates were pressed together until apressure of about 1,362 kg was obtained and the plates were held at thatpressure for about 10 seconds. After heating and applying pressure theplates were removed from the press and cooled allowing the sample tocool.

The cooled backing composite was torn according to the hand tear testoutlined above. Straight line tear was obtained in both the down-web andcross-web directions and the tear was designated a "5" according to thetear test methodology.

Comparative Example 11

This Comparative Example demonstrates that laminating a polymeric filmto a woven cloth as described in U.S. Pat. No. 4,545,843 to Bray is nota suitable method of preparing the woven cloth/polymer backing for theadhesive tape of the invention.

To the extent possible, the protocol outlined in the Bray patent wasfollowed for preparing the comparative samples of this comparativeexample. Bray did not disclose the exact weave density of the fabric.Bleached cotton cheese cloth having a weave density of 44×36 threads per2.5 cm was used for the comparative samples and for the control sample.Polymeric film comprised of ethylene acrylic acid and available asPrimacor 3440 from Dow Chemical of Midland, Mich. was laminated to thecloth.

The following methods were used to laminate the film to the backing. Thepolymeric film and woven cloth were simultaneously passed through a nipcreated by a silicone cast roll and a Teflon (TM) treated steel niproll. The silicone roll was at ambient temperature and the Teflon (TM)treated steel nip roll was heated to the temperature indicated in Table15 below for each sample ranging from ambient temperature to 260° C. Twodifferent methods of placing the cloth and film into the nip were used.Mode A involved placing the polymeric film against the silicone rollleaving the cloth against the nip roll. Mode B involved placing thecloth against the silicone roll leaving the film against the nip roll.The mode each sample was run at is listed in Table 20 below.

The sample backing designated as control was prepared according to theinvention and is described in Example 3 above.

                                      TABLE 20                                    __________________________________________________________________________                                               Tear (1-5)                           (Gurley;  1 = POOR; 5 = GOOD                                                        Nip Temp                                                                           Nip Pressure                                                                        Film Gage                                                                          Speed     seconds/5                                                                              Cross-Web                            Sample # Mode (°C.) (N/lineal cm) (microns) (m/min) Delaminate 0                                                      cc) Curling Web Down-        __________________________________________________________________________    11A  A  93   18-140                                                                              25   1.2 YES   --   YES 1     1                              11B B 93  18 25 1.2 YES -- YES 1 1                                            11C B 93 140 25 1.2 YES >10,000 YES 1 1                                       11D B 107 140 25 1.2 NO 5 YES 3 2                                             11E A 107 140 25 1.2 YES >10,000 YES 1 1                                      11F B 107 140 25 9.8 YES >10,000 YES 1                                        11G B 107 140 75 1.2 YES >10,000 YES 1 1                                      11H B 250 140 25 1.2 NO 1.2 YES 3 1                                           11I B 250 140 25 9.8 YES 1698.5 YES 1 1                                       11J B 300 140 25 1.2 NO 3.8 YES 3 2                                           11K B 171 140 25 1.2 NO 1 YES 1 1                                             11L B 171 140 25 9.8 YES 4.6 YES 1 1                                          11M B 171 140 25 5.5 NO 1.1 YES 3 2                                           11N B 171 140 25 5.5 NO 820 YES 3 2                                           11O B 171 140 25 3.4 NO 2.8 YES 3 3                                           11P B 204 140 25 5.5 YES/NO 1.2 YES 2 1                                       11Q B 204 140 25 7.6 YES 1.0 YES 1 1                                          11R B 204 140 25 3.4 NO 0.6 YES 2 2                                           11S B 204 140 75 5.5 YES 325.0 YES 3 0                                        11T B 260 140 25 9.8 NO 0.3 YES 1 1                                           11U B 260 140 25 12.2 YES/NO 0.5 YES 1-2 2                                    11V B 260 140 75 12.2 YES/NO 369.3 NO 1-2 1                                   Contol B 200 140 75 9.5 NO >10,000 NO 5 5                                   __________________________________________________________________________

The Comparative Samples 11A-11V displayed unacceptable tear in thedown-web and cross-web directions as compared to the Control whichdisplayed acceptable or desirable tear properties in both directions.FIGS. 6 and 7 are top and cross sectional views respectively of sample11O. Although the polymer did not completely encase the cloth as shownin FIG. 6, polymer 30 is not embedded into the cloth fibers 32 so as tobind the crossover points of the warp and weft threads of the wovencloth (FIG. 7).

Some processing problems were encountered when practicing the methoddescribed in the Bray patent When laminating a thin film at hightemperature with a slow speed, a porous backing resulted and otherprocessing problems arose. These included continuous build up of polymerthat melted and flowed through the cloth openings and onto the castroll. The porous cloth laminate had a rough surface due to the polymerflowing through the cloth and attaching to the cast roll. Both of thesewere unacceptable from a process and from a product view point.

Comparative Example 12

This Comparative Example shows that saturating, impregnating orsolvent-ting the polymer onto the woven cloth does not result in thetape backing of the invention.

Woven cloth having a weave density of 44×36 threads per 2.5 cm wascoated using a 15.2 cm wide knife spreader at a 125 micron gap and at a500 micron gap with Kraton 1107 in toluene at 30% solids. FIGS. 2 and 3show the sample resulting from coating the cloth with a 125 micron gap.The fibers of the cloth were encapsulated with the polymer, therefore,the resultant sample did not have the feel of cloth. However, both the125 micron and 500 micron coated cloth had acceptable tear propertiesbetween 4 and 5 on a scale of 1 to 5 where 5 is good and 1 is poor.Porosity testing was done on both samples in 3.4 seconds the 125 micronsample passed 10 cc of air and in 85 seconds and the 500 micron samplepassed 10 cc of air.

Backings prepared according to this comparative example are notacceptable because they lack the feel of cloth.

We claim:
 1. A method of making an adhesive tape comprising the stepsof:a) providing a woven cloth with overlapping fibers and having a firstside and a second side, b) extruding a polyethylene-based polymer ontosaid first side of said woven cloth at a temperature, rate and amount toembed the polymer into the cloth such that the overlapping fibers of thewoven cloth are bound together but the polymer does not extend throughto the second side of the cloth, and c) coating a pressure sensitiveadhesive comprised of a blend of an acrylic and a thermoplasticelastomer, onto at least a portion of said polymer wherein saidresulting adhesive tape is hand tearable in a substantially straightline without fraying and the unwind tension of a roll of the tape isless than 14 N/dm in the absence of a low adhesion backsize.
 2. A methodof making an adhesive tape comprising the steps of:a) providing a wovencloth having a first side and a second side, b) extruding a polymer ontothe first side of the cloth at a temperature, rate and amount effectiveto embed the polymer into the cloth and adhere the polymer to the cloth,and c) coating a pressure sensitive adhesive comprised of a blend of anacrylic pressure-sensitive adhesive and a thermoplastic elastomer coatedonto at least a portion of the polymer, d) wherein (i) the tape is handtearable in a substantially straight line without fraying, and (ii) saidblended comprises at least 5 weight percent adhesive and has amorphology comprising at least two distinct domains, a first domainbeing substantially continuous in nature and said second domain beingfibrillose to schistose in nature parallel to the major surface of theadhesive within said first domain.
 3. A method of making an adhesivetape comprising the steps of:a) providing a woven cloth having a firstside and a second side, b) extruding a polymer onto the first side ofthe cloth at a temperature, rate and amount effective to embed thepolymer into the cloth and adhere the polymer to the cloth, and c)coating a pressure sensitive adhesive comprised of a blend of an acrylicpressure-sensitive adhesive and an elastomer and a tackifier coated ontoat least a portion of the polymer, d) wherein (i) the tape is handtearable in a substantially straight line without fraying, and (ii) saidblend comprises at least 5 weight percent adhesive and has a morphologycomprising at least two distinct domains, a first domain beingsubstantially continuous in nature and said second domain beingfibrillose to schistose in nature parallel to the major surface of theadhesive within said first domain.
 4. The method of claim 1, 2 or 3wherein said tape has a cloth feel on said uncoated side.
 5. The methodof claim 1, 2, or 3 wherein the torn edges of the tape do not curl. 6.The method of claim 1, 2 or 3 wherein said adhesive is selected from thegroup consisting of acrylics, synthetic rubbers, natural rubbers,silicones, and block copolymers.
 7. The method of claim 1, 2 or 3wherein said polymer is comprised of at least two layers.
 8. The methodof claim 1, 2 or 3 wherein said polymer is comprised of at least twodifferent polymers.
 9. The method of claim 1, 2 or 3 wherein saidpolymer is between about 12 and 159 micrometers thick.
 10. The method ofclaim 9 wherein said polymer is between about 25 and 75 micrometersthick.
 11. The method of claim 1, 2 or 3 wherein said woven cloth iscomprised of between about 5×5 to about 300×300 threads per 2.54 cm. 12.The method of claim 1, 2 or 3 wherein said adhesive is extruded ontosaid polymer.
 13. The method of claim 1, 2 or 3 wherein the polymer andthe adhesive are coextruded onto the woven cloth.
 14. An adhesive tapeprepared by the method of claim 1, 2 or
 3. 15. The method of claim 2 or3 wherein said polymer is thermoplastic.
 16. The method of claim 2 or 3wherein said polymer is elastomeric.
 17. The method of claim 2 or 3wherein said polymer is selected from the group consisting ofpolyethylene elastomer, copolymers of polyethylene, blends ofpolyethylene and polyethylene copolymer, ethylene vinyl acetate,polyurethane, block copolymers, polyether block amides, acrylonitrilebutadiene styrene copolymer, polyester block copolymers, polypropylene,polycarbonate, polyacrylics, nylon and blends thereof.